Add VPN and Keystore services and data directories.

-- changed the default mode to 0770 for keystore with the new user 'keystore'.
-- add the keystore service providing the basic key lookup/install/remove, but
  only keystore user can access the key content.
diff --git a/include/private/android_filesystem_config.h b/include/private/android_filesystem_config.h
index a4351ac..4590626 100644
--- a/include/private/android_filesystem_config.h
+++ b/include/private/android_filesystem_config.h
@@ -50,6 +50,7 @@
 #define AID_DHCP          1014  /* dhcp client */
 #define AID_SDCARD_RW     1015  /* external storage write access */
 #define AID_VPN           1016  /* vpn system */
+#define AID_KEYSTORE      1017  /* keystore subsystem */
 
 #define AID_SHELL         2000  /* adb and debug shell user */
 #define AID_CACHE         2001  /* cache access */
@@ -97,7 +98,8 @@
     { "net_bt",    AID_NET_BT, },
     { "sdcard_rw", AID_SDCARD_RW, },
     { "vpn",       AID_VPN, },
-    { "inet",      AID_INET, }, 
+    { "keystore",  AID_KEYSTORE, },
+    { "inet",      AID_INET, },
     { "net_raw",   AID_NET_RAW, },
     { "misc",      AID_MISC, },
     { "nobody",    AID_NOBODY, },