Preserve env variables in run_test part of Concourse ic_gpdb task
Preserve env variables in run_test part of Concourse ic_gpdb task

Some environment variables passed through the pipeline YAML were not
being passed to the test run (e.g. WITH_MIRRORS=false). Removing the
full login flag of su fixes the issue.

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