locked via webdav

added collective.immediatecreate behavior and collective.folderishtypes behavior to Page/Document-Type on a vanilla plone 5.1.2.

when adding a folderishdocument a new object with id "new-document" is created and i am at the edit form. (so far so good)

now i set a title to "test" and click on "save"

```
Traceback (innermost last):

Module ZPublisher.Publish, line 138, in publish
Module ZPublisher.mapply, line 77, in mapply
Module ZPublisher.Publish, line 48, in call_object
Module plone.z3cform.layout, line 63, in __call__
Module plone.z3cform.layout, line 47, in update
Module collective.immediatecreate.editing, line 78, in update
Module plone.z3cform.fieldsets.extensible, line 65, in update
Module plone.z3cform.patch, line 30, in GroupForm_update
Module z3c.form.group, line 145, in update
Module plone.app.z3cform.csrf, line 22, in execute
Module z3c.form.action, line 98, in execute
Module z3c.form.button, line 315, in __call__
Module z3c.form.button, line 170, in __call__
Module collective.immediatecreate.editing, line 39, in handleApply
Module , line 2, in rename
Module plone.api.validation, line 77, in wrapped
Module plone.api.content, line 231, in rename
Module Products.CMFPlone.PloneFolder, line 88, in manage_renameObject
Module OFS.CopySupport, line 355, in manage_renameObject
ResourceLockedError: Object "new-document" is locked via WebDAV
```

seems it comes from plone.locking which does not distinguish between dav- and web-locking.
(i turned off locking behavior on Document-Type and i did not come across this error.)
but as we need locking of plone content and its enabled by default this is sort of a show stopper ...