launcher: Associated the launcher activity with the launch screen theme. Apply default theme in onCreate().

src/main/AndroidManifest.xml

@@ -80,7 +80,7 @@
             android:name=".ui.activity.FileDisplayActivity"
             android:label="@string/app_name"
             android:configChanges="orientation|screenSize"
-            android:theme="@style/Theme.ownCloud.Toolbar.Drawer">
+            android:theme="@style/Theme.ownCloud.Launcher">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

src/main/java/com/owncloud/android/ui/activity/FileDisplayActivity.java

@@ -182,7 +182,8 @@ public class FileDisplayActivity extends HookActivity
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         Log_OC.v(TAG, "onCreate() start");
-
+        // Set the default theme to replace the launch screen theme.
+        setTheme(R.style.Theme_ownCloud_Toolbar_Drawer);
         super.onCreate(savedInstanceState); // this calls onAccountChanged() when ownCloud Account
         // is valid