Change SharedPreferences.Editor.commit() to apply()

Calling SharedPreferences.Editor.commit() from
the main thread results in a synchronous write
to the file system, giving a risk for ANR.

Replace it with asyncronous apply(), which is
safe since the result of commit() was never checked
in the first place.

Bug: 28689077
Test: run with StrictMode on
Change-Id: I63342775f78ba552db8a6a03d8172b43f82be2a9
diff --git a/src/com/android/phone/settings/VoicemailProviderSettingsUtil.java b/src/com/android/phone/settings/VoicemailProviderSettingsUtil.java
index 8187664..3ccd4a3 100644
--- a/src/com/android/phone/settings/VoicemailProviderSettingsUtil.java
+++ b/src/com/android/phone/settings/VoicemailProviderSettingsUtil.java
@@ -137,7 +137,7 @@
         prefs.edit()
                 .putString(key + VM_NUMBER_TAG, null)
                 .putInt(key + FWD_SETTINGS_TAG + FWD_SETTINGS_LENGTH_TAG, 0)
-                .commit();
+                .apply();
     }
 
     private static SharedPreferences getPrefs(Context context) {