[CIFS] if get root inode fails during mount, cleanup tree connection

CC: Stable Kernel <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsfs.c

@@ -174,6 +174,8 @@ out_no_root:
 	cERROR(1, ("cifs_read_super: get root inode failed"));
 	if (inode)
 		iput(inode);
+	
+	cifs_umount(sb, cifs_sb);
 
 out_mount_failed:
 	if (cifs_sb) {