(AIX) backport of master rpm_spec + fix for 2.7.x

This commit can, and should, be trashed when we merge the aix
integration branch into master.
(AIX) Add option tests for various crusty RPMs

Prior to this commit, we had no tests for the changing behaviour based
on version of RPM release. This commit add tests for magical old
versions of RPM, like that on AIX, 3.0.5 aka before the time began.

Sprintly: fixes item:195