Fix alignment of notification action buttons.

Change-Id: Ibfb8f54b6aa59f1c7a56a5e3e8b0c762e48dd496

Author: dsandler

core/res/res/layout/notification_action.xml

@@ -19,5 +19,5 @@
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     style="@android:style/Widget.Holo.Button.Small"
-    android:gravity="left"
+    android:gravity="left|center_vertical"
     />