Bug 36822: LDAP - Add discard_changes

Bug 36822: LDAP - Add discard_changes

Test plan:
1) Apply only LDAP rearrangement patch
2) Run that test file (to prove the rearrangement does not break tests):
$ prove t/db_dependent/Auth_with_ldap.t
3) Verify tests pass
4) Apply LDAP test patch on top
5) Run the test file. Notice it fails.
6) Apply this patch. Run LDAP tests again. Verify tests pass.

Co-authored-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>