Fix buildfarm with regard to pg_audit
Fix buildfarm with regard to pg_audit

Remove the check that pg_audit be installed by
shared_preload_libraries as that's not going to work when running the
regressions tests in the buildfarm.  That check was primairly a nice to
have and isn't required anyway.

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