Delete icon

Summary:
There's a Breeze icon now, so we don't need to ship an old, different, raster image with
Baloo itself anymore.

Test Plan: There's no longer a <install root>/usr/share/icons/hicolor/128x128/apps/baloo.png icon

Reviewers: Baloo, VDG, IlyaBizyaev, ndavis

Reviewed By: VDG, ndavis

Subscribers: kde-frameworks-devel

Tags: Frameworks, Baloo

Differential Revision: https://phabricator.kde.org/D26146