Fix function signatures for logging functions on Python 3.

Review Request #9726 — Created March 4, 2018 and submitted — Latest diff uploaded

Information

Djblets
release-2.0.x
6a4bf29...

Reviewers

We attempt to work around an issue with some older versions of the
logging functions that didn't properly work with keyword arguments.
We used inspect.getargspec() to check for this, but this function is
deprecated and doesn't take into account keyword-only arguments, and
causes warnings on Python 3.

This change switches this over to use inspect.getfullargspec() when
available.

Ran tests (along with other upcoming changes) on Python 2.7, 3.4, 3.5,
and 3.6. I no longer hit any warnings with the logging calls.