Merge "MountService: Force unmount when enabling ums"

        String vs = getVolumeState(path);

        if (enable && vs.equals(Environment.MEDIA_MOUNTED)) {

            mUmsEnabling = enable; // Override for isUsbMassStorageEnabled()

            int rc = doUnmountVolume(path, false);

            int rc = doUnmountVolume(path, true);

            mUmsEnabling = false; // Clear override

            if (rc != StorageResultCode.OperationSucceeded) {

                Log.e(TAG, String.format("Failed to unmount before enabling UMS (%d)", rc));