community/osmscout-server: remove X-GNOME-Autostart phase

Things in the 'panel' phase block gnome-session, and this particular application doesn't seem to be sending any startup notification. This means that DE boot up is blocked for ~90 seconds until gnome-session times out:

gnome-session-binary[2242]: WARNING: Application 'osmscout-server.desktop' failed to register before timeout gnome-session-binary[2242]: CODE_FILE=../gnome-session/gsm-manager.c:CODE_LINE=1389:start_phase:Entering running state

There's no reason I can think of why this needs to be started early in the "gnome boot".