The command gets executed anyway, right? There's an easy fix. Make a
backup copy of your "/etc/hosts" file, and then edit (via sudo gedit)
"/etc/hosts".

Look for a line that contains:

127.0.1.1 LinuxBox3.something

where "something" is likely the workgroup name you entered somewhere.
(On my computer, it was the second line in /etc/hosts.) Get rid of
the ".something" (be sure to delete the "."), so the line reads

127.0.1.1 LinuxBox3

save the file, and reboot.