Tests: Remove invalid certplugin tests
A bunch of certplugin tests were testing number of revoked certificates with
various revocation reasons. Since existence of revoked certificates often
depends on other parts of IdM than IPA, it is not really valid to check their
presence unless creation of revoked certificate is intentionally tested.
https://fedorahosted.org/freeipa/ticket/6349
Reviewed-By: Pavel Vomacka <pvomacka@redhat.com>