Remove outdated comment and clarify code
Remove outdated comment and clarify code

The comment about backporting to a 10 year old version has passed
it's due date so remove. Also actually use the referenced variable
to make the code less confusing to readers (the compiler will be
smart enough about stack allocations anyways). Also reflows and
generally tidies up the comment a little.

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