Gets the JIRA issue associated with the branch name.

        Returns None if no issue with this branch name.

def get_issue(self, branch):
        """
        Gets the JIRA issue associated with the branch name.

        Returns None if no issue with this branch name.
        """
        if branch:
            try:
                issue = self.issue(branch, expand='changelog')
                return issue
            except jira.exceptions.JIRAError as ex:
                if ex.status_code == 404:
                    print "No JIRA issue found for branch %s" % branch
                else:
                    print str(ex)