fix handling missing authors for Bitbucket

The author was accidentally always being initialized as a JSONPathDict,
thus the `if` expression following was always true.

Fixes #733.

buildtrigger/bitbuckethandler.py

@@ -200,8 +200,8 @@ def get_transformed_commit_info(bb_commit, ref, default_branch, repository_name,
 
   match = _RAW_AUTHOR_REGEX.match(commit['raw_author'])
   if match:
-    email_address = match.group(1)
-    author_info = JSONPathDict(lookup_author(email_address))
+    author = lookup_author(match.group(1))
+    author_info = JSONPathDict(author) if author is not None else None
     if author_info:
       config['commit_info.author.username'] = author_info['user.username']
       config['commit_info.author.url'] = 'https://bitbucket.org/%s/' % author_info['user.username']