Clean up Settings and SettingsFragment a bit

Change-Id: I93bf3cb1ea7e8fc09f4ad34b0bdd74f5f5ff1a68
diff --git a/java/res/xml/prefs.xml b/java/res/xml/prefs.xml
index cff7505..da6e601 100644
--- a/java/res/xml/prefs.xml
+++ b/java/res/xml/prefs.xml
@@ -42,7 +42,7 @@
             android:key="popup_on"
             android:title="@string/popup_on_keypress"
             android:persistent="true"
-            android:defaultValue="@bool/config_default_popup_preview" />
+            android:defaultValue="@bool/config_default_key_preview_popup" />
         <ListPreference
             android:key="voice_mode"
             android:title="@string/voice_input"