Remove a comment which is now incorrect.
Remove a comment which is now incorrect.

Before 5d305d86bd917723f09ab4f15c075d90586a210a, this comment was
correct, but now it says we do something which we don't actually do.
Accordingly, remove the comment.

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