setup.py: Import `logging` before calling it.
setup.py: Import `logging` before calling it.

Commit 4dcd960427716289fb3446600a13634215f8d3c6 introduces an exception
handling branch that uses the `logging` module to report an exception to
the user, but fails to import the `logging` module first.

This generated the following error in our CI environment:

03-Oct-2016 17:20:51 	+ python setup.py --command-package stdeb.command sdist_dsc --package python-websocket --source websocket
03-Oct-2016 17:20:51 	Traceback (most recent call last):
03-Oct-2016 17:20:51 	  File "setup.py", line 29, in <module>
03-Oct-2016 17:20:51 	    logging.getLogger(__name__).exception(
03-Oct-2016 17:20:51 	NameError: name 'logging' is not defined

This puts an `import` statement at the location where the `logging`
module is called.

websocket-client/websocket-client