Explicitly install python2-pkgwat-api
For some reason, python2-pkgwat-api conflicts with python-pkgwat-api,
which shipped with F24. This has been reported[0], but this commit works
around the issue by explictly using ``python2``.
[0] https://bugzilla.redhat.com/show_bug.cgi?id=1388544
Signed-off-by: Jeremy Cline <jeremy@jcline.org>