I'm not sure where the travis code comes from but I've got a PR failing because both mod_nss and mod_ssl are installed for some reason when building on the ipa-4-6 branch.
The PR is https://github.com/freeipa/freeipa/pull/1876
All of the travis run-tests have failed.
If you pull the log tarball and look into the journal you'll see something like:
May 07 18:06:15 master.ipa.test httpd[2889]: AH00526: Syntax error on line 5 of /etc/httpd/conf.d/ssl.conf
Line 5 is Listen 443 and mod_nss would have the same so httpd dies.
If you look in ci_results_ipa-4-6.log then mod_ssl is installed as part of
dnf builddep -y -D "with_lint 1" -D "with_wheels 1" --spec freeipa.spec.in --best --allowerasing
mod_nss is subsequently installed because the packages require it.
It sure seems like the builddep is being done on the master branch but I don't see anything in the logs where it is switching to ipa-4-6.
rob