Delete the `remove-old-headers' target, as it is no longer useful. Patch from Alvaro Herrera.
Delete the `remove-old-headers' target, as it is no longer useful. Patch
from Alvaro Herrera.

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