Fix silly initializations (cosmetic only).

Initializing a pointer to "false" isn't per project style,
and reportedly some compilers warn about it (though I've
not seen any such warnings in the buildfarm).

Seems to have come in with commit ff11e7f4, so back-patch
to v12 where that was added.

Didier Gautheron

Discussion: https://postgr.es/m/CAJRYxu+XQuM0qnSqt1Ujztu6fBPzMMAT3VEn6W32rgKG6A2Fsw@mail.gmail.com

src/backend/commands/trigger.c

@@ -2533,7 +2533,7 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 					 TupleTableSlot *slot)
 {
 	TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
-	HeapTuple	newtuple = false;
+	HeapTuple	newtuple = NULL;
 	bool		should_free;
 	TriggerData LocTriggerData;
 	int			i;
@@ -3178,7 +3178,7 @@ ExecIRUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
 {
 	TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 	TupleTableSlot *oldslot = ExecGetTriggerOldSlot(estate, relinfo);
-	HeapTuple	newtuple = false;
+	HeapTuple	newtuple = NULL;
 	bool		should_free;
 	TriggerData LocTriggerData;
 	int			i;