Added missing icons to panel places items

Summary:
Screenshots of the changes:

This contribution was motivated by a comment on Nate's blog.

Reviewers: VDG, ngraham

Reviewed By: VDG, ngraham

Subscribers: ngraham, acrouthamel, kfm-devel

Tags: Dolphin

Differential Revision: https://phabricator.kde.org/D16019