CIFS: Remove extra mutex_unlock in cifs_lock_add_if

to prevent the mutex being unlocked twice if we interrupt a blocked lock.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index ea096ce..91e05f2 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -778,7 +778,6 @@
 		else {
 			mutex_lock(&cinode->lock_mutex);
 			list_del_init(&lock->blist);
-			mutex_unlock(&cinode->lock_mutex);
 		}
 	}