Add "none" for vold and deprecate mkobb -c

If vold isn't told "none" for the key, it will try to mount it as an
encrypted container.

Also remove the -c option from mkobb since it can be triggered by
including a key as well.

Change-Id: I40a8ff3f778bfda682312630e6687ecc14b51844

services/java/com/android/server/MountService.java

@@ -1968,7 +1968,8 @@ class MountService extends IMountService.Stub
                 }
 
                 rc = StorageResultCode.OperationSucceeded;
-                String cmd = String.format("obb mount %s %s %d", mObbState.filename, mKey,
+                String cmd = String.format("obb mount %s %s %d", mObbState.filename,
+                        mKey != null ? mKey : "none",
                         mObbState.callerUid);
                 try {
                     mConnector.doCommand(cmd);