Fix contrib/pg_freespacemap's underestimate of the number of pages it could find in the FSM.  Per report from Dimitri Fontaine and Andrew Gierth.
Fix contrib/pg_freespacemap's underestimate of the number of pages it
could find in the FSM.  Per report from Dimitri Fontaine and Andrew Gierth.

(Affects only 8.2 and 8.3 since HEAD no longer has MaxFSMPages at all.)

rvs/gpdb,cjcjameson/gpdb,50wu/gpdb,ahachete/gpdb,CraigHarris/gpdb,lintzc/gpdb,Chibin/gpdb,0x0FFF/gpdb,xinzweb/gpdb,adam8157/gpdb,0x0FFF/gpdb,chrishajas/gpdb,kaknikhil/gpdb,ahachete/gpdb,rvs/gpdb,cjcjameson/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,edespino/gpdb,50wu/gpdb,lintzc/gpdb,janebeckman/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,chrishajas/gpdb,cjcjameson/gpdb,zaksoup/gpdb,zaksoup/gpdb,xuegang/gpdb,edespino/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,greenplum-db/gpdb,xuegang/gpdb,rvs/gpdb,xuegang/gpdb,Chibin/gpdb,xuegang/gpdb,xinzweb/gpdb,50wu/gpdb,royc1/gpdb,adam8157/gpdb,zaksoup/gpdb,greenplum-db/gpdb,adam8157/gpdb,yuanzhao/gpdb,0x0FFF/gpdb,Chibin/gpdb,kaknikhil/gpdb,yuanzhao/gpdb,adam8157/gpdb,yuanzhao/gpdb,royc1/gpdb,edespino/gpdb,edespino/gpdb,CraigHarris/gpdb,ahachete/gpdb,lintzc/gpdb,ahachete/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,zaksoup/gpdb,yuanzhao/gpdb,janebeckman/gpdb,edespino/gpdb,royc1/gpdb,janebeckman/gpdb,yuanzhao/gpdb,kaknikhil/gpdb,0x0FFF/gpdb,CraigHarris/gpdb,lisakowen/gpdb,cjcjameson/gpdb,yuanzhao/gpdb,royc1/gpdb,xuegang/gpdb,royc1/gpdb,lintzc/gpdb,edespino/gpdb,ashwinstar/gpdb,50wu/gpdb,rvs/gpdb,rvs/gpdb,Chibin/gpdb,greenplum-db/gpdb,lisakowen/gpdb,CraigHarris/gpdb,xuegang/gpdb,zaksoup/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,Quikling/gpdb,xinzweb/gpdb,ashwinstar/gpdb,Quikling/gpdb,yuanzhao/gpdb,xinzweb/gpdb,ashwinstar/gpdb,xinzweb/gpdb,lisakowen/gpdb,lisakowen/gpdb,rvs/gpdb,50wu/gpdb,lisakowen/gpdb,Quikling/gpdb,xuegang/gpdb,chrishajas/gpdb,zaksoup/gpdb,edespino/gpdb,lisakowen/gpdb,chrishajas/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,ahachete/gpdb,Quikling/gpdb,edespino/gpdb,xinzweb/gpdb,xinzweb/gpdb,CraigHarris/gpdb,janebeckman/gpdb,adam8157/gpdb,adam8157/gpdb,cjcjameson/gpdb,50wu/gpdb,CraigHarris/gpdb,Chibin/gpdb,Chibin/gpdb,cjcjameson/gpdb,kaknikhil/gpdb,royc1/gpdb,lisakowen/gpdb,royc1/gpdb,adam8157/gpdb,royc1/gpdb,0x0FFF/gpdb,lintzc/gpdb,chrishajas/gpdb,50wu/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,Quikling/gpdb,lintzc/gpdb,rvs/gpdb,CraigHarris/gpdb,greenplum-db/gpdb,edespino/gpdb,kaknikhil/gpdb,CraigHarris/gpdb,chrishajas/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,Chibin/gpdb,Quikling/gpdb,kaknikhil/gpdb,ahachete/gpdb,cjcjameson/gpdb,greenplum-db/gpdb,rvs/gpdb,chrishajas/gpdb,xuegang/gpdb,adam8157/gpdb,janebeckman/gpdb,janebeckman/gpdb,lintzc/gpdb,jmcatamney/gpdb,janebeckman/gpdb,0x0FFF/gpdb,ashwinstar/gpdb,Quikling/gpdb,jmcatamney/gpdb,janebeckman/gpdb,Chibin/gpdb,edespino/gpdb,lintzc/gpdb,kaknikhil/gpdb,ahachete/gpdb,ahachete/gpdb,Quikling/gpdb,ashwinstar/gpdb,rvs/gpdb,jmcatamney/gpdb,lintzc/gpdb,jmcatamney/gpdb,janebeckman/gpdb,janebeckman/gpdb,rvs/gpdb,yuanzhao/gpdb,Chibin/gpdb,50wu/gpdb,zaksoup/gpdb,chrishajas/gpdb,Chibin/gpdb,kaknikhil/gpdb,0x0FFF/gpdb,zaksoup/gpdb,xuegang/gpdb,Quikling/gpdb,CraigHarris/gpdb,xinzweb/gpdb,lisakowen/gpdb,Quikling/gpdb,0x0FFF/gpdb