Move bootanim and surfaceflinger to class core

They have no dependencies on /data so can be started early.
This permits us to unmount /data while bootanimation is running,
allowing an uninterrupted first boot encryption sequence.

Bug: 17260550
Change-Id: I323fe23e8cf488d8bc136387efdd9fcea96625eb
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 4dd8458..4d4bc86 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -553,7 +553,7 @@
     group radio cache inet misc audio log
 
 service surfaceflinger /system/bin/surfaceflinger
-    class main
+    class core
     user system
     group graphics drmrpc
     onrestart restart zygote
@@ -584,7 +584,7 @@
     # encryption)
 
 service bootanim /system/bin/bootanimation
-    class main
+    class core
     user graphics
     group graphics
     disabled