Prior to this change, the following would fail
nix-shell --pure -p dunst --command dunst
while this would succeed
nix-shell --pure -p dunst -p dbus_daemon --command dunst
because dunst tries to execve 'dbus-launch'. The same issue hit if dunst
was used inside a (user) systemd service (which is what I actually care
about).
This commit eliminates a patch which hard-coded an example configuration file as the program's default settings and prevented the program from reading a user's configuration file.
