Don't ANALYZE external tables.
Don't ANALYZE external tables.

This mirrors the check in vacuum.c, for VACUUMing external tables. This was
missed in commit f995c59f, which replaced most of the old ANALYZE with
the upstream code.

Fixes issue #395, reported by George Caragea.

janebeckman/gpdb,0x0FFF/gpdb,kaknikhil/gpdb,rubikloud/gpdb,lisakowen/gpdb,0x0FFF/gpdb,rubikloud/gpdb,50wu/gpdb,adam8157/gpdb,rvs/gpdb,greenplum-db/gpdb,edespino/gpdb,lisakowen/gpdb,chrishajas/gpdb,yuanzhao/gpdb,tangp3/gpdb,xuegang/gpdb,janebeckman/gpdb,Quikling/gpdb,rvs/gpdb,jmcatamney/gpdb,atris/gpdb,chrishajas/gpdb,adam8157/gpdb,lintzc/gpdb,adam8157/gpdb,0x0FFF/gpdb,zaksoup/gpdb,CraigHarris/gpdb,CraigHarris/gpdb,kaknikhil/gpdb,kaknikhil/gpdb,edespino/gpdb,rvs/gpdb,rvs/gpdb,Chibin/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,lpetrov-pivotal/gpdb,rvs/gpdb,randomtask1155/gpdb,ahachete/gpdb,yuanzhao/gpdb,randomtask1155/gpdb,greenplum-db/gpdb,chrishajas/gpdb,lintzc/gpdb,xinzweb/gpdb,edespino/gpdb,ashwinstar/gpdb,0x0FFF/gpdb,zaksoup/gpdb,janebeckman/gpdb,lpetrov-pivotal/gpdb,zaksoup/gpdb,edespino/gpdb,lpetrov-pivotal/gpdb,jmcatamney/gpdb,lintzc/gpdb,adam8157/gpdb,lisakowen/gpdb,CraigHarris/gpdb,Chibin/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,xuegang/gpdb,lisakowen/gpdb,jmcatamney/gpdb,zaksoup/gpdb,kaknikhil/gpdb,atris/gpdb,kaknikhil/gpdb,50wu/gpdb,tangp3/gpdb,cjcjameson/gpdb,CraigHarris/gpdb,CraigHarris/gpdb,ashwinstar/gpdb,royc1/gpdb,tangp3/gpdb,greenplum-db/gpdb,tangp3/gpdb,rubikloud/gpdb,tangp3/gpdb,zaksoup/gpdb,Quikling/gpdb,jmcatamney/gpdb,Quikling/gpdb,Quikling/gpdb,randomtask1155/gpdb,0x0FFF/gpdb,atris/gpdb,xuegang/gpdb,cjcjameson/gpdb,lpetrov-pivotal/gpdb,cjcjameson/gpdb,Quikling/gpdb,Chibin/gpdb,xuegang/gpdb,adam8157/gpdb,lisakowen/gpdb,ahachete/gpdb,ahachete/gpdb,lintzc/gpdb,CraigHarris/gpdb,lpetrov-pivotal/gpdb,ahachete/gpdb,edespino/gpdb,rubikloud/gpdb,lpetrov-pivotal/gpdb,50wu/gpdb,chrishajas/gpdb,jmcatamney/gpdb,Chibin/gpdb,xinzweb/gpdb,xuegang/gpdb,CraigHarris/gpdb,edespino/gpdb,adam8157/gpdb,edespino/gpdb,chrishajas/gpdb,royc1/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,adam8157/gpdb,cjcjameson/gpdb,xuegang/gpdb,rubikloud/gpdb,0x0FFF/gpdb,kaknikhil/gpdb,royc1/gpdb,kaknikhil/gpdb,Chibin/gpdb,atris/gpdb,yuanzhao/gpdb,Quikling/gpdb,greenplum-db/gpdb,royc1/gpdb,royc1/gpdb,atris/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,rvs/gpdb,randomtask1155/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,lpetrov-pivotal/gpdb,lintzc/gpdb,0x0FFF/gpdb,xuegang/gpdb,Quikling/gpdb,edespino/gpdb,royc1/gpdb,edespino/gpdb,lisakowen/gpdb,0x0FFF/gpdb,Chibin/gpdb,rubikloud/gpdb,Quikling/gpdb,janebeckman/gpdb,ahachete/gpdb,rvs/gpdb,atris/gpdb,jmcatamney/gpdb,rvs/gpdb,yuanzhao/gpdb,janebeckman/gpdb,Chibin/gpdb,janebeckman/gpdb,cjcjameson/gpdb,lintzc/gpdb,jmcatamney/gpdb,adam8157/gpdb,janebeckman/gpdb,zaksoup/gpdb,Chibin/gpdb,tangp3/gpdb,lpetrov-pivotal/gpdb,50wu/gpdb,50wu/gpdb,atris/gpdb,lisakowen/gpdb,Quikling/gpdb,rubikloud/gpdb,CraigHarris/gpdb,50wu/gpdb,royc1/gpdb,tangp3/gpdb,Quikling/gpdb,ahachete/gpdb,randomtask1155/gpdb,lintzc/gpdb,greenplum-db/gpdb,kaknikhil/gpdb,ashwinstar/gpdb,zaksoup/gpdb,rvs/gpdb,greenplum-db/gpdb,lintzc/gpdb,xinzweb/gpdb,ashwinstar/gpdb,xinzweb/gpdb,xinzweb/gpdb,Chibin/gpdb,xuegang/gpdb,jmcatamney/gpdb,randomtask1155/gpdb,kaknikhil/gpdb,chrishajas/gpdb,xinzweb/gpdb,Chibin/gpdb,CraigHarris/gpdb,chrishajas/gpdb,rvs/gpdb,janebeckman/gpdb,lintzc/gpdb,zaksoup/gpdb,50wu/gpdb,ahachete/gpdb,xuegang/gpdb,randomtask1155/gpdb,greenplum-db/gpdb,cjcjameson/gpdb,yuanzhao/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,royc1/gpdb,atris/gpdb,cjcjameson/gpdb,randomtask1155/gpdb,rubikloud/gpdb,ahachete/gpdb,edespino/gpdb,chrishajas/gpdb,janebeckman/gpdb,cjcjameson/gpdb,janebeckman/gpdb,lisakowen/gpdb,xinzweb/gpdb,50wu/gpdb,xinzweb/gpdb,tangp3/gpdb