Btrfs: fix transaction handle leak on failure to create hard link

[ Upstream commit 271dba4521aed0c37c063548f876b49f5cd64b2e ]

If we failed to create a hard link we were not always releasing the
the transaction handle we got before, resulting in a memory leak and
preventing any other tasks from being able to commit the current
transaction.
Fix this by always releasing our transaction handle.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>