Remove unused argument to local function.
Remove unused argument to local function.

add_slice_to_motion doesn't use the sortPathKeys argument for anything, so
let's remove it.

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