bizgres - bizgres: Fix cursors decleared WITH HOLD.

Log Message:
-----------
Fix cursors decleared WITH HOLD. This uncovered some unnoticed bugs created
by previous changes that move where ResLockPortal was being called from. In
this change we:

- Move location of ResUnLockPortal from PortalRun to PortalDrop,
this vastly simplifies most abort and commit handling to the
point where it done mostly from free by the resource owner and
portal managemebnt code.

- Eliminiate ResProcReleaseLocks, ResProcReleaseCurrentOwner and
the complex ResLockReleaseAll in favour of a much simpler
function AtExitCleanup_ResPortals that scans existant portals
and calles ResUnLockPortal if appropriate.

- Add a global variable to count holdable portals and reset
the portalId when appropriate, so we don't run out of available
Ids.

Modified Files:
--------------
bizgres/postgresql/src/backend/commands:
portalcmds.c (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/commands/portalcmds.c.diff?r1=1.5&r2=1.6)
bizgres/postgresql/src/backend/tcop:
pquery.c (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/tcop/pquery.c.diff?r1=1.5&r2=1.6)
bizgres/postgresql/src/backend/utils/init:
postinit.c (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/utils/init/postinit.c.diff?r1=1.4&r2=1.5)
bizgres/postgresql/src/backend/utils/mmgr:
portalmem.c (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/utils/mmgr/portalmem.c.diff?r1=1.5&r2=1.6)
bizgres/postgresql/src/backend/utils/resowner:
resowner.c (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/utils/resowner/resowner.c.diff?r1=1.5&r2=1.6)
bizgres/postgresql/src/backend/utils/resscheduler:
resqueue.c (r1.13 -> r1.14)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/utils/resscheduler/resqueue.c.diff?r1=1.13&r2=1.14)
resscheduler.c (r1.13 -> r1.14)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/backend/utils/resscheduler/resscheduler.c.diff?r1=1.13&r2=1.14)
bizgres/postgresql/src/include/utils:
portal.h (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/include/utils/portal.h.diff?r1=1.5&r2=1.6)
resscheduler.h (r1.11 -> r1.12)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/bizgres/bizgres/postgresql/src/include/utils/resscheduler.h.diff?r1=1.11&r2=1.12)