gpcloud: remove redundant CPP flags
gpcloud: remove redundant CPP flags

PG_CPPFLAGS already has them, don't make differences here.

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