Build: remove ipa.pot from Git as it can be re-generated at any time
All the source files are in the very same repo so there is no point
in keeping the file in Git.
https://fedorahosted.org/freeipa/ticket/6418
Reviewed-By: Martin Basti <mbasti@redhat.com>
Reviewed-By: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Lukas Slebodnik <lslebodn@redhat.com>