Fix UnboundLocalError in releasedocmaker.py

releasedocmaker.py --project HADOOP --project HDFS --project YARN --project MAPREDUCE --projecttitle Apache Hadoop --range --version 2.7.3 --version 3.1.0 --index --license --outputdir HADOOP

Looking for 2.7.3 through 3.1.0
Adding 2.7.3 to the list
Adding 2.7.4 to the list
Adding 2.8.0 to the list
Adding 2.8.1 to the list
Adding 2.9.0 to the list
Adding 3.0.0-alpha1 to the list
Adding 3.0.0-alpha2 to the list
Adding 3.0.0-alpha3 to the list
Adding 3.0.0-beta1 to the list
Traceback (most recent call last):
  File "/Users/aw/shared-vmware/yetus/release-doc-maker/releasedocmaker.py", line 896, in <module>
    main()
  File "/Users/aw/shared-vmware/yetus/release-doc-maker/releasedocmaker.py", line 728, in main
    jlist = sorted(JiraIter(vstr, projects))
  File "/Users/aw/shared-vmware/yetus/release-doc-maker/releasedocmaker.py", line 377, in __init__
    self.jiras = JiraIter.collect_jiras(ver, projects)
  File "/Users/aw/shared-vmware/yetus/release-doc-maker/releasedocmaker.py", line 356, in collect_jiras
    data = JiraIter.query_jira(ver, projects, pos)
  File "/Users/aw/shared-vmware/yetus/release-doc-maker/releasedocmaker.py", line 319, in query_jira
    return JiraIter.load_jira(params, 0)
  File "/Users/aw/shared-vmware/yetus/release-doc-maker/releasedocmaker.py", line 327, in load_jira
    JiraIter.retry_load(resp, params, fail_count)
UnboundLocalError: local variable 'resp' referenced before assignment