Description of problem:
When installing, if a non-ascii text is sent as hostname during Host Configuration, the installer will crash.

Version-Release number of selected component (if applicable):
3.1.0

How reproducible:
Always

Steps to Reproduce:
1. atomic-openshift-installer install
2. press Y
3. press Enter
4. enter a non-ascii symbol (Ж)

Actual results:

Enter hostname or IP address: []: env1-ose3-masterювуьщюдфт
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 991, in invoke
    return _process_result(sub_ctx.command.invoke(sub_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 542, in install
    oo_cfg = get_missing_info_from_user(oo_cfg)
  File "/usr/lib/python2.7/site-packages/ooinstall/cli_installer.py", line 294, in get_missing_info_from_user
    oo_cfg.hosts = collect_hosts()
  File "/usr/lib/python2.7/site-packages/ooinstall/cli_installer.py", line 108, in collect_hosts
    value_proc=validate_prompt_hostname)
  File "/usr/lib/python2.7/site-packages/click/termui.py", line 89, in prompt
    result = value_proc(value)
  File "/usr/lib/python2.7/site-packages/ooinstall/cli_installer.py", line 37, in validate_prompt_hostname
    'and re-enter it.'.format(hostname))
  File "/usr/lib/python2.7/site-packages/click/exceptions.py", line 71, in __init__
    UsageError.__init__(self, message, ctx)
  File "/usr/lib/python2.7/site-packages/click/exceptions.py", line 38, in __init__
    ClickException.__init__(self, message)
  File "/usr/lib/python2.7/site-packages/click/exceptions.py", line 14, in __init__
    message = message.encode('utf-8')
UnicodeDecodeError: 'ascii' codec can't decode byte 0xd1 in position 17: ordinal not in range(128)

Expected results:

Enter hostname or IP address: []: env1-ose3-masterювуьщюдфт
Error: invalid input