Add bootanimation to audio group so it can play boot sound

Bug: 17674304

Change-Id: I5d31bc024fa36fedac2c0ba5c4a8b100937183ad
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 681324a..8ba7c10 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -586,7 +586,7 @@
 service bootanim /system/bin/bootanimation
     class core
     user graphics
-    group graphics
+    group graphics audio
     disabled
     oneshot