Fix two NULL related warnings in resource queue/groups

Passing InvalidOid to as a HeapTuple argument cause a warning for
NULL pointer constant, replace InvalidOid with NULL in call to
AlterResqueueCapabilityEntry() to avoid. Also initialize the owner
in GetResGroupIdForRole() since we otherwise read an uninitialized
value in case the CurrentResourceOwner was set.

src/backend/commands/queue.c

@@ -585,7 +585,7 @@ AlterResqueueCapabilityEntry(Oid queueid,
 												  resTypeInt,
 												  pResSetting,
 												  rel,
-												  InvalidOid);
+												  NULL /* InvalidOid */);
 		}
 
 	} /* end foreach elem */

src/backend/commands/resgroupcmds.c

@@ -329,7 +329,7 @@ Oid
 GetResGroupIdForRole(Oid roleid)
 {
 	HeapTuple	tuple;
-	ResourceOwner owner;
+	ResourceOwner owner = NULL;
 	Oid			groupId;
 	Relation	rel;
 	ScanKeyData	key;