fix AppCompat theme crash

Fixes #2084
// FREEBIE

res/values-v11/themes.xml

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<resources>
-
-    <style name="TextSecure.Light.Dialog" parent="@android:style/Theme.Holo.Light.Dialog"/>
-
-</resources>

res/values/themes.xml

@@ -160,7 +160,7 @@
     </style>
 
     <style name="TextSecure.Light.Dialog"
-           parent="@android:style/Theme.Dialog"
+           parent="Theme.AppCompat.Dialog"
            tools:ignore="NewApi">
         <item name="android:windowFrame">@null</item>
         <item name="android:windowTitleStyle">@style/TextSecureDialogWindowTitle</item>