FIX: If no Disk service cv_linux throw exception
FIX: If no Disk service cv_linux throw exception

If you don't have Disk service register with current host the plugin
will throw an exception when printing "Service found",
s.get_full_name().

This commit prevent printing this message if service isn't found.

vizvayu/mod-webui,rednach/mod-webui,lermit/mod-webui,Simage/mod-webui,lermit/mod-webui,mohierf/mod-webui,shinken-monitoring/mod-webui,Simage/mod-webui,Simage/mod-webui,shinken-monitoring/mod-webui,shinken-monitoring/mod-webui,mohierf/mod-webui,mohierf/mod-webui,GPCsolutions/mod-webui,GPCsolutions/mod-webui,lermit/mod-webui,Simage/mod-webui,vizvayu/mod-webui,lermit/mod-webui,rednach/mod-webui,GPCsolutions/mod-webui,GPCsolutions/mod-webui,rednach/mod-webui