(pdb-468)(packaging) Fix package build on systemd platforms

The previous commit added the defaults file to /etc/sysconfig for
Fedora 19 or Fedora 20, but neglected to create the /etc/sysconfig
directory in the RPM buildroot.

This commit creates the proper directory in the buildroot for builds
on Fedora >= 19 and EL >=7 (systemd platforms)
Merge pull request #866 from shrug/1.6.x

(pdb-468)(packaging) Fix package build on systemd platforms