Fixed $service_name in Debian distrobutions to use 'smartmontools'

See:
https://packages.debian.org/wheezy/amd64/smartmontools/filelist
https://packages.debian.org/sid/amd64/smartmontools/filelist
http://packages.ubuntu.com/lucid/amd64/smartmontools/filelist
http://packages.ubuntu.com/trusty/amd64/smartmontools/filelist