init: allow mediaserver to tag socket (group net_bw_acct)

The mediaserver needs to do communication on behalf of other apps
(browser, ...).
It needs to be able to tag sockets. The kernel will check for net_bw_acct
group membership.

Change-Id: I7fb063fdb7d9435d7f979df6622ff17f34049cbc
diff --git a/rootdir/init.rc b/rootdir/init.rc
index e2832d8..8d6bf97 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -413,7 +413,7 @@
 service media /system/bin/mediaserver
     class main
     user media
-    group audio camera inet net_bt net_bt_admin
+    group audio camera inet net_bt net_bt_admin net_bw_acct
     ioprio rt 4
 
 service bootanim /system/bin/bootanimation