Mobile game restarts when using Application.Quit - unity3d

Question

Okay, so I upgrade my old 4.6 Unity project into Unity 5.0. Overall, the process was relatively painless, but now my Quit button doesn't work when I build for Android.
And I get a very odd message via logcat:
E/Unity (23691): RenderTexture warning: Destroying active render texture. Switching to main context.
E/Unity (23691):
E/Unity (23691): (Filename: Line: 295)
E/Unity (23691):
My quit code in my GameController script is pretty simple:
public void Quit () {
Application.Quit();
}
void OnApplicationQuit () {
if (showAds) { //just in case
adController.DestroyAll();
}
}
What should I be looking for? Is it a texture issue? I do have a custom shader, but the game worked fine with Unity 4.6 before.

Answer 1

So, it all went back to Unity5 and how it integrates older plugins like Admob. Apparently, there is no ProxyActivity needed anymore for Android builds. So I completely removed the following out of the AndroidManifest.xml file:
<activity android:name="com.unity3d.player.UnityPlayerProxyActivity" android:label="#string/app_name" android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen" >
<meta-data android:name="unityplayer.ForwardNativeEventsToDalvik" android:value="true" />
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
And then moved the <intent-filter> into the UnityPlayerActivity:
<activity android:name="com.unity3d.player.UnityPlayerActivity" android:label="#string/app_name" android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
Now Application.Quit() works no problem!
Complete AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:installLocation="preferExternal" package="com.example.admobtest" android:versionName="1.0" android:versionCode="1">
<supports-screens android:smallScreens="true" android:normalScreens="true" android:largeScreens="true" android:xlargeScreens="true" android:anyDensity="true" />
<!-- Mobile Ads Permissions -->
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application android:icon="#drawable/app_icon" android:label="#string/app_name" android:debuggable="false">
<!-- meta-data tag for Google Play services -->
<meta-data android:name="com.google.android.gms.version" android:value="#integer/google_play_services_version"/>
<activity android:name="com.unity3d.player.UnityPlayerActivity" android:label="#string/app_name" android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.unity3d.player.UnityPlayerNativeActivity" android:label="#string/app_name" android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen" >
<meta-data android:name="unityplayer.ForwardNativeEventsToDalvik" android:value="true" />
<meta-data android:name="android.app.lib_name" android:value="unity" />
</activity>
<activity android:name="com.unity3d.player.VideoPlayer" android:label="#string/app_name" android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen" >
</activity>
<!-- Google Mobile Ads Activity -->
<activity android:name="com.google.android.gms.ads.AdActivity"
android:label="#string/app_name"
android:theme="#android:style/Theme.Translucent"
android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
</activity>
<!-- PurpleBrain AdBuddiz Activity -->
<activity android:name="com.purplebrain.adbuddiz.sdk.AdBuddizActivity"
android:label="#string/app_name"
android:theme="#android:style/Theme.Translucent">
</activity>
</application>
<uses-feature android:glEsVersion="0x00020000" />
<uses-sdk android:minSdkVersion="9" android:targetSdkVersion="19" />
</manifest>

Answer 2

#theprisoner6 aswer doesn't work for me but for reference the another option is to hide an application (move it to back). This has added value that if the Android decide it is worth to keep the app in memory you will avoid loading an application which should improve user experience. This could be handled as a plugin but hey, there is no need for that! Very simple C# code:
AndroidJavaClass jc = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
AndroidJavaObject jo = jc.GetStatic<AndroidJavaObject>("currentActivity");
var movedToBack = jo.Call<bool>("moveTaskToBack", true);
Swap that code with Application.Quit() and you are done.