fs/cifs: fix gcc warning in sid_to_id

fix warning [-Wunused-but-set-variable] at variable 'rc',
keeping the code readable.
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsacl.c

@@ -342,7 +342,7 @@ static int
 sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid,
 		struct cifs_fattr *fattr, uint sidtype)
 {
-	int rc;
+	int rc = 0;
 	struct key *sidkey;
 	char *sidstr;
 	const struct cred *saved_cred;
@@ -450,11 +450,12 @@ sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid,
 	 * fails then we just fall back to using the mnt_uid/mnt_gid.
 	 */
 got_valid_id:
+	rc = 0;
 	if (sidtype == SIDOWNER)
 		fattr->cf_uid = fuid;
 	else
 		fattr->cf_gid = fgid;
-	return 0;
+	return rc;
 }
 
 int