xfs:free bp in xlog_find_tail() error path

xlog_find_tail() currently leaks a bp on one error path.

There is no error target, so manually free the bp before
returning the error.

Found by Coverity.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

fs/xfs/xfs_log_recover.c

@@ -964,6 +964,7 @@ xlog_find_tail(
 	}
 	if (!found) {
 		xfs_warn(log->l_mp, "%s: couldn't find sync record", __func__);
+		xlog_put_bp(bp);
 		ASSERT(0);
 		return XFS_ERROR(EIO);
 	}