get_version() throws jenkins.BadHTTPException when login is required

[Bao Haojun]

Our site is set up so that all users need to login first, before they can see anything.

Because of that, when I call get_version, it will fail with the following:

    >>> server.get_version()
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/home/bhj/.linuxbrew/Cellar/python@2/2.7.16/lib/python2.7/site-packages/jenkins/__init__.py", line 835, in get_version
        % self.server)
    jenkins.BadHTTPException: Error communicating with server[server url]

It can be fixed by the following patch:

    diff --git a/jenkins/__init__.py b/jenkins/__init__.py
    index 9717f58..b443756 100755
    --- a/jenkins/__init__.py
    +++ b/jenkins/__init__.py
    @@ -826,7 +826,7 @@ class Jenkins(object):
             try:
                 request = requests.Request('GET', self._build_url(''))
                 request.headers['X-Jenkins'] = '0.0'
    - response = self._response_handler(self._request(request))
    + response = self.jenkins_request(request)

                 return response.headers['X-Jenkins']