Use correct container for ipa-4-5 testing
    
    @freeipa/freeipa-master no longer provides Fedora 25 dependencies
    but is still used in the current container for testing ipa-4-5.
    Since ipa-4-5 won't pass F26 pylint check we can't use the master
    branch container, thus we'll use an ad hoc one.
    
    Reviewed-By: Pavel Vomacka <pvomacka@redhat.com>