Fix timestamp in end-of-recovery WAL records.
Fix timestamp in end-of-recovery WAL records.

We used time(null) to set a TimestampTz field, which gave bogus results.
Noticed while looking at pg_xlogdump output.

Backpatch to 9.3 and above, where the fast promotion was introduced.

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