#2427: Standard conforming string default (#2429)
#2427: Standard conforming string default (#2429)

* #2427: changing the description, default, and set classification of standard_conforming_string to match code)

* small edit

* changing set classification to 'session'

janebeckman/gpdb,ashwinstar/gpdb,rvs/gpdb,edespino/gpdb,cjcjameson/gpdb,lisakowen/gpdb,50wu/gpdb,adam8157/gpdb,Quikling/gpdb,edespino/gpdb,ashwinstar/gpdb,xinzweb/gpdb,janebeckman/gpdb,50wu/gpdb,Quikling/gpdb,Quikling/gpdb,Chibin/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,janebeckman/gpdb,ashwinstar/gpdb,kaknikhil/gpdb,xinzweb/gpdb,rvs/gpdb,jmcatamney/gpdb,adam8157/gpdb,cjcjameson/gpdb,kaknikhil/gpdb,greenplum-db/gpdb,Quikling/gpdb,xinzweb/gpdb,greenplum-db/gpdb,Quikling/gpdb,cjcjameson/gpdb,janebeckman/gpdb,Chibin/gpdb,Quikling/gpdb,rvs/gpdb,rvs/gpdb,jmcatamney/gpdb,50wu/gpdb,jmcatamney/gpdb,edespino/gpdb,Chibin/gpdb,kaknikhil/gpdb,adam8157/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,Quikling/gpdb,greenplum-db/gpdb,adam8157/gpdb,kaknikhil/gpdb,Chibin/gpdb,edespino/gpdb,cjcjameson/gpdb,yuanzhao/gpdb,lisakowen/gpdb,50wu/gpdb,yuanzhao/gpdb,edespino/gpdb,adam8157/gpdb,greenplum-db/gpdb,Quikling/gpdb,yuanzhao/gpdb,janebeckman/gpdb,yuanzhao/gpdb,rvs/gpdb,rvs/gpdb,janebeckman/gpdb,kaknikhil/gpdb,lisakowen/gpdb,50wu/gpdb,rvs/gpdb,jmcatamney/gpdb,kaknikhil/gpdb,lisakowen/gpdb,jmcatamney/gpdb,xinzweb/gpdb,edespino/gpdb,edespino/gpdb,xinzweb/gpdb,Chibin/gpdb,rvs/gpdb,cjcjameson/gpdb,cjcjameson/gpdb,jmcatamney/gpdb,kaknikhil/gpdb,rvs/gpdb,yuanzhao/gpdb,adam8157/gpdb,yuanzhao/gpdb,50wu/gpdb,Quikling/gpdb,yuanzhao/gpdb,Chibin/gpdb,xinzweb/gpdb,lisakowen/gpdb,Chibin/gpdb,ashwinstar/gpdb,kaknikhil/gpdb,lisakowen/gpdb,cjcjameson/gpdb,rvs/gpdb,yuanzhao/gpdb,adam8157/gpdb,50wu/gpdb,kaknikhil/gpdb,ashwinstar/gpdb,Chibin/gpdb,cjcjameson/gpdb,edespino/gpdb,edespino/gpdb,lisakowen/gpdb,lisakowen/gpdb,edespino/gpdb,greenplum-db/gpdb,50wu/gpdb,Chibin/gpdb,xinzweb/gpdb,janebeckman/gpdb,greenplum-db/gpdb,janebeckman/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,Chibin/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,janebeckman/gpdb,Quikling/gpdb,ashwinstar/gpdb,adam8157/gpdb,xinzweb/gpdb,greenplum-db/gpdb,cjcjameson/gpdb,greenplum-db/gpdb,janebeckman/gpdb