Minor cleanup of PQunescapeBytea().  Avoid unportable assumptions about behavior of malloc and realloc when request size is 0.  Fix escape sequence recognizer so that only valid 3-digit octal sequences are treated as escape sequences ... isdigit() is not a correct test.
Minor cleanup of PQunescapeBytea().  Avoid unportable assumptions about
behavior of malloc and realloc when request size is 0.  Fix escape
sequence recognizer so that only valid 3-digit octal sequences are
treated as escape sequences ... isdigit() is not a correct test.

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