manage-projects is inscrutable on gerrit failures

[Robert Collins]

gerritlib is to blame, but consider:
# manage-projects
/usr/local/lib/python2.7/dist-packages/paramiko/client.py:95: UserWarning: Unknown ssh-rsa host key for [localhost]:29418: e862bb16532032940655481160e98419
  (key.get_name(), hostname, hexlify(key.get_fingerprint())))
Traceback (most recent call last):
  File "/usr/local/bin/manage-projects", line 10, in <module>
    sys.exit(main())
  File "/usr/local/lib/python2.7/dist-packages/jeepyb/cmd/manage_projects.py", line 358, in main
    gerrit.createProject(project)
  File "/usr/local/lib/python2.7/dist-packages/gerritlib/gerrit.py", line 126, in createProject
    out, err = self._ssh(cmd)
  File "/usr/local/lib/python2.7/dist-packages/gerritlib/gerrit.py", line 184, in _ssh
    raise Exception("Gerrit error executing %s" % command)
Exception: Gerrit error executing gerrit create-project --require-change-id --name testing-cabal/testtools
#

gerrit logs the output as debug, but manage-projects has no facility for setting the log level/logging to a file etc.