Various cosmetic code cleanup for PL/Python:
Various cosmetic code cleanup for PL/Python:

- use "bool" rather than "int" for boolean variables

- use "PLy_malloc" rather than "malloc" in two places

- define "PLy_strdup", and use it rather than malloc() + strcpy() in
  two places (which should have been memcpy(), anyway).

- remove a bunch of redundant parentheses from expressions that do not
  need the parentheses for code clarity

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