Set the default task count to the node count based upon actual allocation

(it can vary if node range is specified "-N2-8").

src/srun/srun.c

@@ -328,6 +328,8 @@ _allocate_nodes(void)
 		}
 		sigaction(SIGINT, &old_action, NULL);
 	}
+	if (!opt.nprocs_set)	/* can vary by min-max node count */
+		opt.nprocs = resp->node_cnt;
 
 	return resp;
 }