Keep heap open until new heap generated in RMV.
Keep heap open until new heap generated in RMV.

Early close became apparent when invalidation messages were
processed in a new location under CLOBBER_CACHE_ALWAYS builds, due
to additional locking.

Back-patch to 9.3

techdragon/Postgres-XL,zeroae/postgres-xl,jmcatamney/gpdb,ovr/postgres-xl,adam8157/gpdb,greenplum-db/gpdb,xinzweb/gpdb,adam8157/gpdb,zeroae/postgres-xl,jmcatamney/gpdb,xinzweb/gpdb,greenplum-db/gpdb,xinzweb/gpdb,50wu/gpdb,pavanvd/postgres-xl,xinzweb/gpdb,ashwinstar/gpdb,oberstet/postgres-xl,lisakowen/gpdb,50wu/gpdb,Postgres-XL/Postgres-XL,jmcatamney/gpdb,Postgres-XL/Postgres-XL,adam8157/gpdb,lisakowen/gpdb,greenplum-db/gpdb,ovr/postgres-xl,techdragon/Postgres-XL,ashwinstar/gpdb,adam8157/gpdb,ashwinstar/gpdb,Postgres-XL/Postgres-XL,50wu/gpdb,50wu/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,lisakowen/gpdb,50wu/gpdb,oberstet/postgres-xl,yazun/postgres-xl,lisakowen/gpdb,pavanvd/postgres-xl,oberstet/postgres-xl,yazun/postgres-xl,techdragon/Postgres-XL,ashwinstar/gpdb,pavanvd/postgres-xl,greenplum-db/gpdb,ovr/postgres-xl,50wu/gpdb,jmcatamney/gpdb,adam8157/gpdb,50wu/gpdb,techdragon/Postgres-XL,Postgres-XL/Postgres-XL,jmcatamney/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,lisakowen/gpdb,xinzweb/gpdb,pavanvd/postgres-xl,adam8157/gpdb,ashwinstar/gpdb,xinzweb/gpdb,greenplum-db/gpdb,lisakowen/gpdb,greenplum-db/gpdb,Postgres-XL/Postgres-XL,adam8157/gpdb,lisakowen/gpdb,oberstet/postgres-xl,ovr/postgres-xl,50wu/gpdb,pavanvd/postgres-xl,lisakowen/gpdb,yazun/postgres-xl,xinzweb/gpdb,oberstet/postgres-xl,techdragon/Postgres-XL,xinzweb/gpdb,zeroae/postgres-xl,adam8157/gpdb,zeroae/postgres-xl,zeroae/postgres-xl,ashwinstar/gpdb,yazun/postgres-xl,greenplum-db/gpdb,ovr/postgres-xl,yazun/postgres-xl