Description of problem:
Packstack unit tests are failing on RHEL-based machine or docker image.

Tested on 
> uname -a
Linux test-node 3.10.0-327.28.3.el7.x86_64 #1 SMP Fri Aug 12 13:21:05 EDT 2016 x86_64 x86_64 x86_64 GNU/Linux
> uname -a
Linux docker-image 3.10.0-327.18.2.el7.x86_64 #1 SMP Fri Apr 8 05:09:53 EDT 2016 x86_64 x86_64 x86_64 GNU/Linux

Version-Release number of selected component (if applicable):
2b29648d20ef22aee6f67ad25fbe932137f30bfd (master)
98cc90f7226d415c4163ee644f9e609d4aa11fe5 (stable/mitaka)
5df800fa09ac5b44da334a08319919b59194f655 (stable/liberty)

How reproducible:
100%

Steps to Reproduce:
0. Running on RHEL 7.2
1. git clone https://review.rdoproject.org/r/openstack/packstack
2. cd packstack
3. tox -epy27

Actual results:
tox -epy27
GLOB sdist-make: /home/jenkins/jroot/workspace/ci-test-unit/workspace/openstack-packstack/setup.py
py27 create: /home/jenkins/jroot/workspace/ci-test-unit/workspace/openstack-packstack/.tox/py27
py27 installdeps: -r/home/jenkins/jroot/workspace/ci-test-unit/workspace/openstack-packstack/tools/pip-requires, -r/home/jenkins/jroot/workspace/ci-test-unit/workspace/openstack-packstack/tools/test-requires
py27 inst: /home/jenkins/jroot/workspace/ci-test-unit/workspace/openstack-packstack/.tox/dist/packstack-mitaka-rc2.zip
py27 installed: cffi==1.8.3,coverage==4.2,cryptography==1.5.2,docutils==0.12,enum34==1.1.6,flake8==2.1.0,hacking==0.9.6,idna==2.1,ipaddress==1.0.17,mccabe==0.2.1,netaddr==0.7.18,nose==1.3.7,packstack===mitaka-rc2,pbr==1.10.0,pep8==1.5.6,pyasn1==0.1.9,pycparser==2.14,pyflakes==0.8.1,pyOpenSSL==16.1.0,PyYAML==3.12,six==1.10.0
py27 runtests: PYTHONHASHSEED='2686720743'
py27 runtests: commands[0] | nosetests
...............................E
======================================================================
ERROR: Make sure RHN password is quoted.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jenkins/jroot/workspace/ci-test-unit/workspace/openstack-packstack/tests/test_plugin_prescript.py", line 34, in test_rhn_creds_quoted
    prescript_000.controller.CONF["CONFIG_KEYSTONE_HOST"] = "1.2.3.4"
AttributeError: 'module' object has no attribute 'controller'

----------------------------------------------------------------------
Ran 32 tests in 1.645s

FAILED (errors=1)
ERROR: InvocationError: '/home/jenkins/jroot/workspace/ci-test-unit/workspace/openstack-packstack/.tox/py27/bin/nosetests'
___________________________________ summary ____________________________________
ERROR:   py27: commands failed


Expected results:
Unit Tests pass

Additional info:
The issue does not exist on Centos because the code is not executed:

cat tests/test_plugin_prescript.py

# On non-RHEL, the CONFIG_{RH,SATELLITE} options are never set,
# i.e. this test would always fail. Therefore, only run it on RHEL.
if not prescript_000.is_rhel():
    return