update stune group for cameraserver to top-app

bug 29512132

Change-Id: I1e7787ac8a401ad285816a11c422ddc6bfc98892
diff --git a/camera/cameraserver/cameraserver.rc b/camera/cameraserver/cameraserver.rc
index 624baff..8f6737f 100644
--- a/camera/cameraserver/cameraserver.rc
+++ b/camera/cameraserver/cameraserver.rc
@@ -4,4 +4,4 @@
     group audio camera input drmrpc inet media mediadrm net_bt net_bt_admin net_bw_acct
     ioprio rt 4
     writepid /dev/cpuset/camera-daemon/tasks
-    writepid /dev/stune/foreground/tasks
+    writepid /dev/stune/top-app/tasks