Description of problem:
Failed to install when using "-c" to specify a configuration as non-root user

Version-Release number of selected component (if applicable):
atomic-openshift-utils-3.0.20-1.git.0.3703f1b.el7aos.noarch

How reproducible:
Always

Steps to Reproduce:
1.Switch to a non-root user before installation
2.Write a configuration of installer.cfg.yml to install
3.Execute "atomic-openshift-installer -c installer.cfg.yml install"

Actual results:
Traceback (most recent call last):
  File "/usr/bin/atomic-openshift-installer", line 9, in <module>
    load_entry_point('ooinstall==3.0.0', 'console_scripts', 'oo-install')()
  File "/usr/lib/python2.7/site-packages/click/core.py", line 664, in __call__
    return self.main(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/click/core.py", line 644, in main
    rv = self.invoke(ctx)
  File "/usr/lib/python2.7/site-packages/click/core.py", line 988, in invoke
    Command.invoke(self, ctx)
  File "/usr/lib/python2.7/site-packages/click/core.py", line 837, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/lib/python2.7/site-packages/click/core.py", line 464, in invoke
    return callback(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/ooinstall/cli_installer.py", line 648, in cli
    oo_cfg = OOConfig(ctx.obj['configuration'])
  File "/usr/lib/python2.7/site-packages/ooinstall/oo_config.py", line 118, in __init__
    self._set_defaults()
  File "/usr/lib/python2.7/site-packages/ooinstall/oo_config.py", line 178, in _set_defaults
    os.makedirs(self.settings['ansible_inventory_directory'])
  File "/usr/lib64/python2.7/os.py", line 157, in makedirs
    mkdir(name, mode)
OSError: [Errno 13] Permission denied: '/.ansible'

Expected results:
Install successfully. using "~" dir instead of "/" dir while making dir can avoid the issue.

Additional info: