remove an unused variable waitingForSignal

Remove an unused variable waitingForSignal in /storage/lmgr/proc.c.
I guess it was there because orignally PG uses singals to implement
ProcWaitForSignal() stuff, so we may need to remember the process status.
But now we don't need it.

Index: proc.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v
retrieving revision 1.156
diff -c -r1.156 proc.c
*** proc.c 31 Dec 2004 22:01:05 -0000 1.156
--- proc.c 11 Apr 2005 03:08:39 -0000
***************
*** 74,80 ****
static PGPROC *DummyProcs = NULL;

static bool waitingForLock = false;
- static bool waitingForSignal = false;

/* Mark these volatile because they can be changed by signal handler */
static volatile bool statement_timeout_active = false;
--- 74,79 ----
***************
*** 962,970 ****
void
ProcWaitForSignal(void)
{
- waitingForSignal = true;
PGSemaphoreLock(&MyProc->sem, true);
- waitingForSignal = false;
}

/*
--- 961,967 ----
***************
*** 978,984 ****
ProcCancelWaitForSignal(void)
{
PGSemaphoreReset(&MyProc->sem);
- waitingForSignal = false;
}

/*
--- 975,980 ----