Merge branch 'kdumpmem' into 'master'

CA-188288 Tweaks to guest memory checks

This change takes into account the crashdump kernel when checking how much RAM is in use in a guest (can account for 6-7% of a typical guest's RAM), and increases the overall tolerance to 4% to cover some more borderline scenarios.

Tested in jobid 1224819 (rhel511 doesn't have a crashdump kernel, while rhel66 does)

See merge request !128