In cases where smb4php returns false of an empty array stat/( has to return false.
Fixes #3466 because the test method of external filesystems uses stat() to detect if the given parameters are okay.

Changes to 3rdparty are necessary as well:
https://github.com/owncloud/3rdparty/pull/33
Merge pull request #3567 from owncloud/fixing-3466

In cases where smb4php returns false of an empty array stat/( has to ret...