Description of problem:
While trying to download a package while offline the output shows a python exception.

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


How reproducible:


Steps to Reproduce:
1. Update all the repo data
2. Switch networking off
3. try to dnf update or dnf install something

Actual results:
Is this ok [y/N]: y
Downloading Packages:
Traceback (most recent call last):
  File "/bin/dnf", line 35, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 272, in user_main
    errcode = main(args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 64, in main
    return _main(base, args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 187, in _main
    return_code, resultmsgs = base.do_transaction()
  File "/usr/lib/python2.7/site-packages/dnf/cli/cli.py", line 185, in do_transaction
    self.download_callback_total_cb)
  File "/usr/lib/python2.7/site-packages/dnf/base.py", line 1033, in download_packages
    librepo.download_packages(targets)
  File "/usr/lib64/python2.7/site-packages/librepo/__init__.py", line 1035, in download_packages
    return _librepo.download_packages(list, failfast)
librepo.LibrepoException: (8, "Curl error: Couldn't resolve host name for https://mirrors.fedoraproject.org/metalink?repo=fedora-20&arch=x86_64", 'An Curl handle error')


Expected results:
A user friendly output stating that there is no internet connectivity

Additional info: