orangefs: Fix sb refcount leak when allocate sb info failed.

The reference counting issue happens in one exception handling
path of orangefs_mount(). When failing to allocate sb info, the
function forgets to decrease the refcount of sb increased by
sget(), causing a refcount leak.

Fix this issue by jumping to the label "free_sb_and_op" instead
of "free_op"
Signed-off-by: Chenyuan Mi <cymi20@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

fs/orangefs/super.c

@@ -526,7 +526,7 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
 	sb->s_fs_info = kzalloc(sizeof(struct orangefs_sb_info_s), GFP_KERNEL);
 	if (!ORANGEFS_SB(sb)) {
 		d = ERR_PTR(-ENOMEM);
-		goto free_op;
+		goto free_sb_and_op;
 	}
 
 	ret = orangefs_fill_sb(sb,