Change from logging to logger because we wish to see the information about the module where the logging message came from so that it's easier to diagnosing problems.

I changed logging to logger in modules reviews, webapi and ssh.

Test using the tests in the reviews, webapi and ssh modules' repositories. Using the following commands:
./tests/runtests.py reviewboard.reviews.tests
./tests/runtests.py reviewboard.webapi.tests
./tests/runtests.py reviewboard.ssh.tests

All three test sets are passed.