Fix compose styles.

This is why reply/reply all switcher didn't have the correct
background assets.

Change-Id: I9deff726175dc4b376d59bb44696a3a4518fe50d
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index cc65400..99854d8 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -58,7 +58,8 @@
             </intent-filter>
             <meta-data android:name="android.app.searchable" android:resource="@xml/searchable" />
         </activity>
-        <activity android:name=".compose.ComposeActivity">
+        <activity android:name=".compose.ComposeActivity"
+            android:theme="@android:style/Theme.Holo.Light">
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
                 <action android:name="android.intent.action.SENDTO" />