Bug 778491 - Make about:home last tabs text correctly centered. r=sriram

mobile/android/base/resources/layout/abouthome_last_tabs_row.xml

@@ -21,6 +21,7 @@
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               android:layout_toRightOf="@id/last_tab_favicon"
+              android:layout_marginTop="2dip"
               android:layout_marginLeft="12dip"
               android:layout_marginRight="12dip"
               android:textSize="15sp"