The exc_callback was expecting the old update_entry signature,
(dn, attrs). This was changed to just (entry) for ticket #2660,
see http://www.freeipa.org/page/HowTo/Migrate_your_code_to_the_new_LDAP_API.

Update the exc_callback to expect the entry as first argument,
and add some tests.

https://fedorahosted.org/freeipa/ticket/4309

Reviewed-By: Martin Kosek <mkosek@redhat.com>

Reviewed-By: Adam Misnyovszki <amisnyov@redhat.com>

New decorator: ui_driver.screenshot created. It should be applied on test methods.

Screenshot is saved on each exception except SkipTest.

Configuration:
- add: `save_screenshots: True` to ~/.ipa/ui_test.conf to enable saving screenshots
- optionally add `screenshot_dir: /path/to/dir` to specify target directory
  otherwise screenshots are saved to current directory

Reviewed-By: Adam Misnyovszki <amisnyov@redhat.com>

Range test extended with checking of disabled
field according to trust types.

Reviewed-By: Petr Vobornik <pvoborni@redhat.com>

Added a callback feature to webui tests,
to extend functionality. Also added
assert_disabled function to ui_driver, to
check if a field is disabled in the browser.

Reviewed-By: Petr Vobornik <pvoborni@redhat.com>

Reviewed-By: Jakub Hrozek <jhrozek@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

Reviewed-By: Jakub Hrozek <jhrozek@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

Reviewed-By: Jakub Hrozek <jhrozek@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

Reviewed-By: Jakub Hrozek <jhrozek@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

Reviewed-By: Tomas Babej <tbabej@redhat.com>