Make --log wait automatically in run (#764)

Summary:
Pull Request resolved: #764

I generally used to find it confusing and assume that `--log` was broken before realizing I always need to specify `--wait` to make it work -- I think it would be better to have `--log` automatically wait for the job to finish.

Differential Revision: D48874784

fbshipit-source-id: 728325213d695b5077b8b4139e42b763875d8a91

torchx/cli/cmd_run.py

@@ -223,7 +223,7 @@ def _run(self, runner: Runner, args: argparse.Namespace) -> None:
                     app_status = runner.status(app_handle)
                     if app_status:
                         logger.info(app_status.format())
-                    if args.wait:
+                    if args.wait or args.log:
                         self._wait_and_exit(runner, app_handle, log=args.log)
 
         except (ComponentValidationException, ComponentNotFoundException) as e: