Alikins/productid use rpm label compare

Fix for https://bugzilla.redhat.com/show_bug.cgi?id=1086301

The product cert product version comparison was two naive. So it
needs to be at least somewhat smarter, how much smarter is open.

This version pulls in rpm.labelCompare, and uses the rpm version comparison
to compare two numbers. That is at least well known and understood, and can
handle most odd version compares.

But it does add a new use of rpm python module.