Display first / in mounted storage access description

Summary:
Since f299edfeb8fd3893f9adf71a277f21a5ed50775u, for a mounted nfs drive in its description we have :
what/is/mounted on from-where-ip

This patch changes this to:
/what/is/mounted on from-where-ip

The description is what is displayed in places for instance.

Reviewers: Frameworks, bruns, ngraham, broulik

Reviewed By: ngraham, broulik

Subscribers: kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D26098