Add occ command acceptance tests

[phil-davis]

cli acceptance tests now exist in core.

General QA issue owncloud/QA#570

• check that extra non-LDAP local users and groups can be created, modified, deleted. Add CLI tests for user and groups #337
• check that LDAP-defined users can be deleted locally, but can "come back" again (because they are synced from LDAP) Add CLI tests for user and groups #337
• check that LDAP-defined groups can be deleted locally, but can "come back" again (because they are synced from LDAP) Add cli test for deleting ldap group. #342
• check what can/cannot happen with respect to modifying attributes of LDAP users using occ commands Add tests for checking if admin can modify LDAP defined attributes #341
  (clues in comment Dont use preferences table quota any longer core#32731 (comment) )

[phil-davis]

Also review what Provisioning API and webUI acceptance tests for LDAP-specific cases already exist, and add scenarios to fill out coverage of the items above.

[dpakach]

Completed in PRs #337 , #341, #342