Change glowbar.svgz to smoother style
The old style was weird. When the screen edge feature was enabled for the sides of screens, it looked like a bunch of dots smooshed together. Now it's one smooth bar.
Reviewers: VDG, rooty
Reviewed By: rooty
Subscribers: rooty, rapiteanu, kde-frameworks-devel
Differential Revision: https://phabricator.kde.org/D18834