Don't send an empty SSPI negotiation packet at the end of the negotiation.
Don't send an empty SSPI negotiation packet at the end of the negotiation.

Fixes bug #3750

ahachete/gpdb,cjcjameson/gpdb,techdragon/Postgres-XL,jmcatamney/gpdb,50wu/gpdb,Quikling/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,cjcjameson/gpdb,snaga/postgres-xl,zaksoup/gpdb,ahachete/gpdb,arcivanov/postgres-xl,edespino/gpdb,kaknikhil/gpdb,CraigHarris/gpdb,50wu/gpdb,Quikling/gpdb,ahachete/gpdb,kmjungersen/PostgresXL,Chibin/gpdb,0x0FFF/gpdb,lisakowen/gpdb,lisakowen/gpdb,cjcjameson/gpdb,chrishajas/gpdb,kaknikhil/gpdb,Postgres-XL/Postgres-XL,Postgres-XL/Postgres-XL,pavanvd/postgres-xl,0x0FFF/gpdb,zeroae/postgres-xl,techdragon/Postgres-XL,arcivanov/postgres-xl,adam8157/gpdb,arcivanov/postgres-xl,zaksoup/gpdb,snaga/postgres-xl,CraigHarris/gpdb,rvs/gpdb,ovr/postgres-xl,chrishajas/gpdb,rvs/gpdb,CraigHarris/gpdb,janebeckman/gpdb,kaknikhil/gpdb,lintzc/gpdb,arcivanov/postgres-xl,adam8157/gpdb,cjcjameson/gpdb,Quikling/gpdb,xuegang/gpdb,greenplum-db/gpdb,snaga/postgres-xl,greenplum-db/gpdb,snaga/postgres-xl,postmind-net/postgres-xl,kaknikhil/gpdb,rvs/gpdb,xuegang/gpdb,ahachete/gpdb,ovr/postgres-xl,oberstet/postgres-xl,0x0FFF/gpdb,yazun/postgres-xl,royc1/gpdb,cjcjameson/gpdb,chrishajas/gpdb,Chibin/gpdb,zaksoup/gpdb,jmcatamney/gpdb,cjcjameson/gpdb,CraigHarris/gpdb,adam8157/gpdb,jmcatamney/gpdb,Quikling/gpdb,xinzweb/gpdb,lintzc/gpdb,ahachete/gpdb,Chibin/gpdb,postmind-net/postgres-xl,0x0FFF/gpdb,kmjungersen/PostgresXL,kaknikhil/gpdb,50wu/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,royc1/gpdb,chrishajas/gpdb,lisakowen/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,xinzweb/gpdb,ovr/postgres-xl,lisakowen/gpdb,yazun/postgres-xl,pavanvd/postgres-xl,chrishajas/gpdb,tpostgres-projects/tPostgres,50wu/gpdb,zeroae/postgres-xl,zaksoup/gpdb,ahachete/gpdb,zaksoup/gpdb,zaksoup/gpdb,xuegang/gpdb,rvs/gpdb,yazun/postgres-xl,50wu/gpdb,zaksoup/gpdb,xuegang/gpdb,tpostgres-projects/tPostgres,edespino/gpdb,CraigHarris/gpdb,ahachete/gpdb,xuegang/gpdb,Postgres-XL/Postgres-XL,lintzc/gpdb,tpostgres-projects/tPostgres,zeroae/postgres-xl,cjcjameson/gpdb,Chibin/gpdb,0x0FFF/gpdb,chrishajas/gpdb,kaknikhil/gpdb,yuanzhao/gpdb,janebeckman/gpdb,greenplum-db/gpdb,xinzweb/gpdb,CraigHarris/gpdb,Chibin/gpdb,yuanzhao/gpdb,xinzweb/gpdb,xuegang/gpdb,kaknikhil/gpdb,Quikling/gpdb,CraigHarris/gpdb,kmjungersen/PostgresXL,ahachete/gpdb,pavanvd/postgres-xl,postmind-net/postgres-xl,0x0FFF/gpdb,yuanzhao/gpdb,postmind-net/postgres-xl,xuegang/gpdb,Quikling/gpdb,xinzweb/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,lintzc/gpdb,kmjungersen/PostgresXL,50wu/gpdb,xinzweb/gpdb,Chibin/gpdb,xinzweb/gpdb,Chibin/gpdb,edespino/gpdb,edespino/gpdb,janebeckman/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,rvs/gpdb,cjcjameson/gpdb,0x0FFF/gpdb,lintzc/gpdb,royc1/gpdb,oberstet/postgres-xl,janebeckman/gpdb,xinzweb/gpdb,royc1/gpdb,ashwinstar/gpdb,pavanvd/postgres-xl,Quikling/gpdb,ashwinstar/gpdb,royc1/gpdb,techdragon/Postgres-XL,lisakowen/gpdb,arcivanov/postgres-xl,Chibin/gpdb,adam8157/gpdb,lintzc/gpdb,oberstet/postgres-xl,janebeckman/gpdb,techdragon/Postgres-XL,Postgres-XL/Postgres-XL,tpostgres-projects/tPostgres,tpostgres-projects/tPostgres,yuanzhao/gpdb,kaknikhil/gpdb,jmcatamney/gpdb,adam8157/gpdb,xuegang/gpdb,rvs/gpdb,Postgres-XL/Postgres-XL,adam8157/gpdb,royc1/gpdb,ovr/postgres-xl,rvs/gpdb,Quikling/gpdb,oberstet/postgres-xl,Quikling/gpdb,lintzc/gpdb,lisakowen/gpdb,edespino/gpdb,oberstet/postgres-xl,kaknikhil/gpdb,lintzc/gpdb,royc1/gpdb,zeroae/postgres-xl,ashwinstar/gpdb,techdragon/Postgres-XL,jmcatamney/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,janebeckman/gpdb,ashwinstar/gpdb,lisakowen/gpdb,yazun/postgres-xl,janebeckman/gpdb,50wu/gpdb,janebeckman/gpdb,royc1/gpdb,CraigHarris/gpdb,0x0FFF/gpdb,adam8157/gpdb,cjcjameson/gpdb,yazun/postgres-xl,rvs/gpdb,edespino/gpdb,edespino/gpdb,Quikling/gpdb,rvs/gpdb,ashwinstar/gpdb,Chibin/gpdb,xuegang/gpdb,janebeckman/gpdb,janebeckman/gpdb,zeroae/postgres-xl,zaksoup/gpdb,rvs/gpdb,jmcatamney/gpdb,pavanvd/postgres-xl,snaga/postgres-xl,edespino/gpdb,ovr/postgres-xl,greenplum-db/gpdb,postmind-net/postgres-xl,Chibin/gpdb,edespino/gpdb,lintzc/gpdb,CraigHarris/gpdb,edespino/gpdb,50wu/gpdb,chrishajas/gpdb,arcivanov/postgres-xl,adam8157/gpdb,chrishajas/gpdb,kmjungersen/PostgresXL,ashwinstar/gpdb,jmcatamney/gpdb,lisakowen/gpdb