Update comment to fix nibble mention:
Update comment to fix nibble mention:

	 * We are not sure how much precision is in tv_usec, so we
	 * swap the high and low 16 bits of 'later' and XOR them with
	 * 'earlier'. On the off chance that the result is 0, we
	 * loop until it isn't.

Greg Stark

ashwinstar/gpdb,ashwinstar/gpdb,edespino/gpdb,greenplum-db/gpdb,snaga/postgres-xl,ahachete/gpdb,janebeckman/gpdb,kaknikhil/gpdb,xuegang/gpdb,royc1/gpdb,greenplum-db/gpdb,chrishajas/gpdb,greenplum-db/gpdb,foyzur/gpdb,foyzur/gpdb,Chibin/gpdb,greenplum-db/gpdb,Quikling/gpdb,foyzur/gpdb,rubikloud/gpdb,lisakowen/gpdb,janebeckman/gpdb,techdragon/Postgres-XL,ovr/postgres-xl,edespino/gpdb,yazun/postgres-xl,tangp3/gpdb,yuanzhao/gpdb,rvs/gpdb,zeroae/postgres-xl,xuegang/gpdb,lintzc/gpdb,Postgres-XL/Postgres-XL,rubikloud/gpdb,kaknikhil/gpdb,jmcatamney/gpdb,ovr/postgres-xl,kaknikhil/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,lpetrov-pivotal/gpdb,50wu/gpdb,foyzur/gpdb,tpostgres-projects/tPostgres,lpetrov-pivotal/gpdb,kaknikhil/gpdb,rubikloud/gpdb,oberstet/postgres-xl,cjcjameson/gpdb,Quikling/gpdb,randomtask1155/gpdb,kaknikhil/gpdb,50wu/gpdb,zeroae/postgres-xl,rubikloud/gpdb,0x0FFF/gpdb,50wu/gpdb,CraigHarris/gpdb,lintzc/gpdb,chrishajas/gpdb,adam8157/gpdb,tangp3/gpdb,kaknikhil/gpdb,tangp3/gpdb,atris/gpdb,0x0FFF/gpdb,ahachete/gpdb,tpostgres-projects/tPostgres,lintzc/gpdb,Chibin/gpdb,Chibin/gpdb,oberstet/postgres-xl,cjcjameson/gpdb,ovr/postgres-xl,atris/gpdb,tpostgres-projects/tPostgres,pavanvd/postgres-xl,snaga/postgres-xl,jmcatamney/gpdb,foyzur/gpdb,lisakowen/gpdb,xinzweb/gpdb,lintzc/gpdb,edespino/gpdb,chrishajas/gpdb,lpetrov-pivotal/gpdb,tpostgres-projects/tPostgres,rvs/gpdb,lintzc/gpdb,adam8157/gpdb,greenplum-db/gpdb,lintzc/gpdb,zaksoup/gpdb,CraigHarris/gpdb,xinzweb/gpdb,yuanzhao/gpdb,janebeckman/gpdb,randomtask1155/gpdb,0x0FFF/gpdb,ahachete/gpdb,Postgres-XL/Postgres-XL,50wu/gpdb,pavanvd/postgres-xl,lpetrov-pivotal/gpdb,xuegang/gpdb,50wu/gpdb,randomtask1155/gpdb,edespino/gpdb,xuegang/gpdb,yuanzhao/gpdb,randomtask1155/gpdb,chrishajas/gpdb,zaksoup/gpdb,ahachete/gpdb,rvs/gpdb,lintzc/gpdb,cjcjameson/gpdb,oberstet/postgres-xl,yuanzhao/gpdb,yuanzhao/gpdb,zaksoup/gpdb,zeroae/postgres-xl,royc1/gpdb,Quikling/gpdb,arcivanov/postgres-xl,adam8157/gpdb,zeroae/postgres-xl,ahachete/gpdb,zeroae/postgres-xl,janebeckman/gpdb,kmjungersen/PostgresXL,techdragon/Postgres-XL,xuegang/gpdb,royc1/gpdb,atris/gpdb,0x0FFF/gpdb,rvs/gpdb,atris/gpdb,janebeckman/gpdb,royc1/gpdb,lintzc/gpdb,rubikloud/gpdb,cjcjameson/gpdb,jmcatamney/gpdb,postmind-net/postgres-xl,janebeckman/gpdb,rvs/gpdb,chrishajas/gpdb,xinzweb/gpdb,zaksoup/gpdb,atris/gpdb,lpetrov-pivotal/gpdb,rubikloud/gpdb,CraigHarris/gpdb,CraigHarris/gpdb,cjcjameson/gpdb,Quikling/gpdb,ovr/postgres-xl,randomtask1155/gpdb,pavanvd/postgres-xl,kaknikhil/gpdb,kmjungersen/PostgresXL,foyzur/gpdb,edespino/gpdb,0x0FFF/gpdb,Quikling/gpdb,tangp3/gpdb,xuegang/gpdb,tangp3/gpdb,kmjungersen/PostgresXL,arcivanov/postgres-xl,janebeckman/gpdb,kaknikhil/gpdb,edespino/gpdb,xuegang/gpdb,edespino/gpdb,adam8157/gpdb,pavanvd/postgres-xl,lisakowen/gpdb,Postgres-XL/Postgres-XL,xinzweb/gpdb,royc1/gpdb,ahachete/gpdb,CraigHarris/gpdb,arcivanov/postgres-xl,xuegang/gpdb,Quikling/gpdb,ashwinstar/gpdb,arcivanov/postgres-xl,edespino/gpdb,ashwinstar/gpdb,chrishajas/gpdb,ovr/postgres-xl,jmcatamney/gpdb,xinzweb/gpdb,zaksoup/gpdb,rubikloud/gpdb,ahachete/gpdb,lisakowen/gpdb,kmjungersen/PostgresXL,CraigHarris/gpdb,rvs/gpdb,tangp3/gpdb,lpetrov-pivotal/gpdb,cjcjameson/gpdb,rvs/gpdb,50wu/gpdb,yazun/postgres-xl,atris/gpdb,50wu/gpdb,adam8157/gpdb,royc1/gpdb,arcivanov/postgres-xl,yuanzhao/gpdb,Quikling/gpdb,Chibin/gpdb,Postgres-XL/Postgres-XL,atris/gpdb,ashwinstar/gpdb,yazun/postgres-xl,techdragon/Postgres-XL,yazun/postgres-xl,Chibin/gpdb,lisakowen/gpdb,rvs/gpdb,jmcatamney/gpdb,lisakowen/gpdb,50wu/gpdb,greenplum-db/gpdb,techdragon/Postgres-XL,jmcatamney/gpdb,foyzur/gpdb,postmind-net/postgres-xl,lisakowen/gpdb,jmcatamney/gpdb,foyzur/gpdb,ahachete/gpdb,yazun/postgres-xl,lisakowen/gpdb,tangp3/gpdb,lpetrov-pivotal/gpdb,zaksoup/gpdb,0x0FFF/gpdb,oberstet/postgres-xl,lpetrov-pivotal/gpdb,cjcjameson/gpdb,atris/gpdb,Chibin/gpdb,Chibin/gpdb,0x0FFF/gpdb,yuanzhao/gpdb,Quikling/gpdb,CraigHarris/gpdb,rubikloud/gpdb,oberstet/postgres-xl,ashwinstar/gpdb,janebeckman/gpdb,jmcatamney/gpdb,royc1/gpdb,cjcjameson/gpdb,CraigHarris/gpdb,zaksoup/gpdb,janebeckman/gpdb,edespino/gpdb,techdragon/Postgres-XL,randomtask1155/gpdb,xinzweb/gpdb,CraigHarris/gpdb,Postgres-XL/Postgres-XL,snaga/postgres-xl,ashwinstar/gpdb,zaksoup/gpdb,randomtask1155/gpdb,Chibin/gpdb,pavanvd/postgres-xl,snaga/postgres-xl,yuanzhao/gpdb,Chibin/gpdb,randomtask1155/gpdb,cjcjameson/gpdb,tpostgres-projects/tPostgres,greenplum-db/gpdb,tangp3/gpdb,royc1/gpdb,postmind-net/postgres-xl,Quikling/gpdb,postmind-net/postgres-xl,janebeckman/gpdb,Quikling/gpdb,xinzweb/gpdb,yuanzhao/gpdb,arcivanov/postgres-xl,rvs/gpdb,chrishajas/gpdb,0x0FFF/gpdb,chrishajas/gpdb,snaga/postgres-xl,postmind-net/postgres-xl,lintzc/gpdb,adam8157/gpdb,yuanzhao/gpdb,edespino/gpdb,ashwinstar/gpdb,Chibin/gpdb,adam8157/gpdb,xinzweb/gpdb,greenplum-db/gpdb,xuegang/gpdb,rvs/gpdb,adam8157/gpdb,kmjungersen/PostgresXL,kaknikhil/gpdb