Fixed @throws hint

`\LogicException => \PHPCR\RepositoryException`

It's a real BC break but only in docblock.
What about introduce `UnauthenticatedException`?
i would say so. and instead explain in the class doc that all methods except the descriptor call and login() obviously needs a login first or it will throw the RepositoryException. maybe other interfaces in this folder have the same throws note, which we should remove as well.

its kind of obvious i think, and something that should not be possible to happen in normal jackalope operation. and its not like java where we technically must declare exceptions that may be thrown...