Fix comments in StrategyNotifyBgWriter().
Fix comments in StrategyNotifyBgWriter().

The interface for the function was changed in
d72731a70450b5e7084991b9caa15cb58a2820df but the comments of the
function was not updated.

Patch by Yugo Nagata.

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