It seems like there's an upstream bug in the "lpstat" command. We need
to specify the server's port.
Further information: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=711327
[root@client:~]# lpstat -H
/var/run/cups/cups.sock
[root@client:~]# lpstat -h server -H
/var/run/cups/cups.sock:631
[root@client:~]# CUPS_SERVER=server lpstat -H
server:631
[root@client:~]# lpstat -h server:631 -H
server:631