Title: #872: Add IPA-specific bind unit file
During upgrade of Fedora 25 to 26, when FreeIPA is installed with
DNS, bind attempts to start before KDC which leads to a failed
start because it requires a ticket to connect to LDAP.
Add an own unit file with a dependency which sets bind to start
after the KDC service.
To pull the PR as Git branch:
git remote add ghfreeipa https://github.com/freeipa/freeipa
git fetch ghfreeipa pull/872/head:pr872
git checkout pr872