init.rc: add inet permission to VPN daemons explicitly.

Racoon still needs it after dropping root privilege, or pure IPSec VPN
will fail. Mtpd works without it because net_raw implies inet. However
it would be better to set all of them clearly without the assumption.

Change-Id: I50762af2c25ec9cc559e528c7b14f469494fd553

rootdir/init.rc

@@ -487,15 +487,15 @@ service racoon /system/bin/racoon
     class main
     socket racoon stream 600 system system
     # IKE uses UDP port 500. Racoon will setuid to vpn after binding the port.
-    group vpn net_admin
+    group vpn net_admin inet
     disabled
     oneshot
 
 service mtpd /system/bin/mtpd
     class main
     socket mtpd stream 600 system system
     user vpn
-    group vpn net_admin net_raw
+    group vpn net_admin inet net_raw
     disabled
     oneshot