pg_prewarm: Add missing LWLockRegisterTranche call.
pg_prewarm: Add missing LWLockRegisterTranche call.

Commit 79ccd7cbd5ca44bee0191d12e9e65abf702899e7, which added automatic
prewarming, neglected this.

Kyotaro Horiguchi, reviewed by me.

Discussion: 5568fbdd7460419c1b6bcf8c3cc365641b37e338@lab.ntt.co.jp

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