Move application icon to mipmap-* directories

Change-Id: Idc5df7046d0fa64ffbfce2869dffb4fe0fd144a0
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index dc388d0..97ac3d7 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -56,7 +56,9 @@
                 android:description="@string/permission_access_provider_desc"/>
     <uses-permission android:name="com.android.email.permission.ACCESS_PROVIDER"/>
 
-    <application android:icon="@drawable/icon" android:label="@string/app_name"
+    <application
+        android:icon="@mipmap/icon"
+        android:label="@string/app_name"
         android:name="Email"
         android:theme="@android:style/Theme.Holo.Light"
         android:hardwareAccelerated="false"