ipatests: add upgrade test for double-encoded cacert
Create a test for upgrade with the following scenario:
- install master
- write a double-encoded cert in the entry
cn=cacert,,cn=ipa,cn=etc,$basedn
to simulate bug 7775
- call ipa-server-upgrade
- check that the upgrade fixed the value
The upgrade should finish successfully and repair
the double-encoded cert.
Related to https://pagure.io/freeipa/issue/7775
Reviewed-By: Christian Heimes <cheimes@redhat.com>