get rid of git commit sha value as surffix of dafault installation path (#3530)
get rid of git commit sha value as surffix of dafault installation path (#3530)

Signed-off-by: Peifeng Qiu <5ac57522f17d595d0e5c6d4a23fb4fdcd3f0c5e9@pivotal.io>
greenplum-db/gpdb,50wu/gpdb,edespino/gpdb,adam8157/gpdb,lisakowen/gpdb,ashwinstar/gpdb,50wu/gpdb,ashwinstar/gpdb,Chibin/gpdb,adam8157/gpdb,edespino/gpdb,adam8157/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,xinzweb/gpdb,adam8157/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,50wu/gpdb,50wu/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,xinzweb/gpdb,edespino/gpdb,edespino/gpdb,50wu/gpdb,greenplum-db/gpdb,edespino/gpdb,yuanzhao/gpdb,xinzweb/gpdb,jmcatamney/gpdb,xinzweb/gpdb,yuanzhao/gpdb,edespino/gpdb,50wu/gpdb,jmcatamney/gpdb,lisakowen/gpdb,Chibin/gpdb,50wu/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,adam8157/gpdb,ashwinstar/gpdb,adam8157/gpdb,adam8157/gpdb,lisakowen/gpdb,edespino/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,Chibin/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,xinzweb/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,lisakowen/gpdb,lisakowen/gpdb,lisakowen/gpdb,edespino/gpdb,Chibin/gpdb,xinzweb/gpdb,jmcatamney/gpdb,Chibin/gpdb,50wu/gpdb,ashwinstar/gpdb,Chibin/gpdb,ashwinstar/gpdb,lisakowen/gpdb,Chibin/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,xinzweb/gpdb,Chibin/gpdb,lisakowen/gpdb,adam8157/gpdb,xinzweb/gpdb,edespino/gpdb,edespino/gpdb,ashwinstar/gpdb,Chibin/gpdb,Chibin/gpdb