Common: check_expired_locked_rules use SQLalchemy

[voetberg]

Address part of #127 - Update without Prometheus

[dchristidis]

Please split your PR into multiple commits. You can take #138 as an example.

It may seem tedious for such a small and simple probe, but it’s a good habit, one that should be adopted early.

[dchristidis]

You’re also porting the probe from Python 2 to Python 3, but that is not described in your commits. The changes to the shebang and the print statements should be split in a separate commit.

In case you’re not convinced by the usefulness of this, there was a print 'Locked expired rules' statement that you silently removed. It required effort from me to notice it; it would have been obvious if the changes had been split as recommended.

[dchristidis]

This blank line (and the similar one you introduced later) produces a curious grouping. According to PEP 8:

Use blank lines in functions, sparingly, to indicate logical sections.

A try and its associated except statements are typically part of the same section. It would make more sense to introduce a blank line before the second try statement and before the last sys.exit(status) call.