if the libreoffice wrapper doesn't find a dbus instance in the
environment it starts one, but then neglects to clean it up. over time
this can litter the system with orphaned dbus instances. kill the daemon
as well instead of just removing the socket directory.
LibreOffice doesn't know where to look for hunspell dictionaries on
NixOS but we can use the DICPATH env var to point to them. Now
spellchecking with system dictionaries works.
Note that some of these dictionaries are built from LibreOffice repos -
this is preferable to building them as part of LO as other applications
can use them.
