Replace merge/swap icons in InCallUI.

Change-Id: I721dbfcac28add9f5cea4326a0cefb5384fa44a6
diff --git a/InCallUI/res/drawable/btn_merge.xml b/InCallUI/res/drawable/btn_merge.xml
index 080949a..78e1974 100644
--- a/InCallUI/res/drawable/btn_merge.xml
+++ b/InCallUI/res/drawable/btn_merge.xml
@@ -21,9 +21,9 @@
     <item android:drawable="@drawable/btn_background" />
 
     <item>
-        <bitmap android:src="@drawable/ic_merge_holo_dark"
+        <bitmap android:src="@drawable/ic_toolbar_merge"
             android:gravity="center"
             android:tint="@color/selectable_icon_tint" />
     </item>
-    
+
 </layer-list>
\ No newline at end of file