Description of problem:
There is currently no gpgcheck line in "/etc/yum.repos.d/fedora-devel.repo",
which makes it harder to switch off gpg checking, if one happens
to have an unsigned mirror of fedora/devel.

It probably wouldn't do any harm to add one to fedora-extras-devel.repo too.

Steps to Reproduce:
1. Do new rawhide install from unsigned tree.
2. Change fedora-devel.repo to point to local repo.
3. Turn off gpgcheck for local devel yum repo.
  
Actual results:
Need to edit /etc/yum.conf as well or add gpgcheck line by hand.

Expected results:
Be able to change "gpgcheck=1" to "gpgcheck=0" easily in fedora-devel.repo.