Include rpmvercmp in list of binaries used by testall.
Fix for package comparisons on RPM's.  Thanks to Nick Anderson.
Renamed yum_compare to rpm_compare.
Change: Add rpmvercmp to rpm package_methods

In order to reliably compare RPM versions we use rpmvercmp instead of an
internal comparison.
Merge pull request #378 from kacfengine/rpmvercmp

Fix for package comparisons on RPM's.