vstloggerpro: do not copy desktop file to /usr/share/applications

Webmenu searches desktop files also from /usr/local/share/applications,
and actually with higher priority.
vstloggerpro: hardcode desktop icon path

Relative icons are searched from /usr/share/icons, but since the
upstream loggerpro package installs everything under /usr/local, we need
to hardcode the icon path here.