Getting an AttributeError if I did not provide any subcommand

[bloodpet]

When I run with just:
$ authenticator

I get this output:

Traceback (most recent call last):
File "/usr/local/bin/authenticator", line 11, in
sys.exit(authenticator_command())
File "/usr/local/lib/python3.5/dist-packages/authenticator/cli.py", line 1241, in authenticator_command
m.execute()
File "/usr/local/lib/python3.5/dist-packages/authenticator/cli.py", line 1198, in execute
if self.args.subcmd not in (
AttributeError: 'Namespace' object has no attribute 'subcmd'

It would be nice to see the usage instead.

[JeNeSuisPasDave]

I hope to fix this before end of 2019. Sorry, but I didn't notice this issue before today. :-(

[4-0-4-notfound]

same here

[bloodpet]

@JeNeSuisPasDave you could merge the PR if that's acceptable. It's a decent fix :)