Fix typo in comment
Fix typo in comment

Author: Amit Langote <fd783a1e5a8d112fd732ee3d51bccc96d6729241@lab.ntt.co.jp>

lisakowen/gpdb,adam8157/gpdb,lisakowen/gpdb,xinzweb/gpdb,xinzweb/gpdb,greenplum-db/gpdb,lisakowen/gpdb,xinzweb/gpdb,50wu/gpdb,adam8157/gpdb,adam8157/gpdb,adam8157/gpdb,adam8157/gpdb,lisakowen/gpdb,greenplum-db/gpdb,50wu/gpdb,50wu/gpdb,greenplum-db/gpdb,adam8157/gpdb,50wu/gpdb,lisakowen/gpdb,lisakowen/gpdb,xinzweb/gpdb,50wu/gpdb,xinzweb/gpdb,xinzweb/gpdb,xinzweb/gpdb,lisakowen/gpdb,greenplum-db/gpdb,xinzweb/gpdb,lisakowen/gpdb,greenplum-db/gpdb,50wu/gpdb,greenplum-db/gpdb,adam8157/gpdb,50wu/gpdb,adam8157/gpdb,50wu/gpdb,greenplum-db/gpdb,greenplum-db/gpdb