Remove a redundant FIXME message
Remove a redundant FIXME message

This FIXME comment indicates that we were hitting an assertion
in the regress test before, so an error message was put in place.
This seems not needed anymore as all regress tests are passed.
If there's an assert failure ever be found again, we should fix the same.

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