Fix bug #16660819 Switchbar text should be white not grey

- use "?android:attr/textColorPrimary" so that we are white
and matching the color of the Activity Title

Change-Id: I18bc47d2080fcc171b86e5b56bfc86bbe8637caa

res/layout/switch_bar.xml

@@ -25,6 +25,7 @@
               android:layout_weight="1"
               android:layout_gravity="center_vertical"
               android:textAppearance="@style/TextAppearance.Switch"
+              android:textColor="?android:attr/textColorPrimary"
               android:textAlignment="viewStart" />
 
     <com.android.settings.widget.ToggleSwitch android:id="@+id/switch_widget"