Hi all, Just now I failed to start ConfigNode after pulling the latest commit from the master branch.
And I found out that the default startup mode -s or -r was not added after 38c1d5 <https://github.com/apache/iotdb/commit/38c1d591acfabdae4bbf542100090652416d2027> commit, and it didn't report an error. So I suggest to add the default startup mode or throw an exception if the user didn't specify the default startup mode.
