Description of problem:
Currently, Satellite is not updating the last_checking for hypervisors unless some change happens in the same.

Version-Release number of selected component (if applicable):

How reproducible:
100%

Steps to Reproduce:
1. configure virt-who and keep it running
2. check after few days
3.

Actual results:
Some hypervisors will get updated, some not.

Expected results:
All the hypervisors are being updated once all of them are still around and with CH already registered.

Additional info:

DEV Tracker for https://issues.redhat.com/browse/SAT-18422
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2008252