[RestClient] Enfore PR limit when using server (#588)

When pulling PRs from bitbucket server, the limit url parameter doesn't
seem to be beeing heeded. This change allows the library to prevent too
many PRs from being returned to the client.

Author: nafeger

atlassian/bitbucket.py

@@ -801,7 +801,7 @@ def get_pull_requests(self, project, repository, state='OPEN', order='newest', l
                 pr_list.extend(response.get("values", []))
 
         else:
-            while not response.get('isLastPage'):
+            while not response.get('isLastPage') and len(pr_list) < limit:
                 start = response.get('nextPageStart')
                 params['start'] = start
                 response = self.get(url, params=params)