[files_external] removing function as it's the same in the base class - THX Robin

Conflicts:
	apps/files_external/lib/smb.php
[files_external] fixing some undefined index
[files_external] fix config gui for all users

backport of 9e05781ec22c3f4e6b89b188332242b03088736e
the path must be encoded because within the smb4pph code it's decoded again - pretty easy but still .....
use urlencode not rawurlencode
Merge pull request #1636 from owncloud/fixing-smb-master

Fixing smb master