ocfs2: Fix error return in ocfs2_write_cluster()

A typo caused ocfs2_write_cluster() to return 0 in some error cases.
Fix it.
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

fs/ocfs2/aops.c

@@ -1301,7 +1301,7 @@ static int ocfs2_write_cluster(struct address_space *mapping,
 		if (tmpret) {
 			mlog_errno(tmpret);
 			if (ret == 0)
-				tmpret = ret;
+				ret = tmpret;
 		}
 	}