Add test for baseldap.entry_to_dict.

Reviewed-By: Petr Viktorin <pviktori@redhat.com>
ipa-adtrust-install does not re-add member in adtrust agents group

When a CIFS service exists and adtrust agents group does not
have it as a member attribute (for whatever reason), re-running
ipa-adtrust-install does not fix the inconsistency.

Make the installer more robust by being able to fix the inconsistency.

https://fedorahosted.org/freeipa/ticket/4464

Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
ipatests: test_trust: Add test to cover lookup of trusdomains

Adds an integration tests that checks that all trustdomains are
able to be found by trustdomain-find command right after the
trust has been established.

Also moves some code to allow easier adding common test cases for
both POSIX and non-POSIX test classes.

https://fedorahosted.org/freeipa/ticket/4208