Unable to generate packstack answer file with packstack --gen-answer-file <file> without configured and working nameserver in Red Hat OpenStack Platform

Issue

Unable to generate packstack answer file with packstack --gen-answer-file <file> without configured and working nameserver in Red Hat OpenStack Platform.

Trying to generate an answer file leads to the following error message

packstack --gen-answer-file <file>
(...)
ERROR:root:Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/packstack/installer/run_setup.py", line 955, in main
    initPluginsConfig()
  File "/usr/lib/python2.7/site-packages/packstack/installer/run_setup.py", line 932, in initPluginsConfig
    plugin.initConfig(controller)
  File "/usr/lib/python2.7/site-packages/packstack/plugins/prescript_000.py", line 337, in initConfig
    "DEFAULT_VALUE": utils.get_localhost_ip(),
  File "/usr/lib/python2.7/site-packages/packstack/installer/utils/network.py", line 57, in get_localhost_ip
    raise NetworkError('Local IP address discovery failed. Please set '
NetworkError: Local IP address discovery failed. Please set nameserver correctly.


ERROR : Local IP address discovery failed. Please set nameserver correctly.
Traceback (most recent call last):
  File "/usr/bin/packstack", line 15, in <module>
    run_setup.main()
  File "/usr/lib/python2.7/site-packages/packstack/installer/run_setup.py", line 1024, in main
    print(output_messages.ERR_CHECK_LOG_FILE_FOR_MORE_INFO % (logFile))
UnboundLocalError: local variable 'logFile' referenced before assignment