Fix VACUUM_TRUNCATE_LOCK_WAIT_INTERVAL
Fix VACUUM_TRUNCATE_LOCK_WAIT_INTERVAL

lazy_truncate_heap() was waiting for
VACUUM_TRUNCATE_LOCK_WAIT_INTERVAL, but in microseconds
not milliseconds as originally intended.

Found by code inspection.

Simon Riggs

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