This update for systemd-rpm-macros fixes the following issues:

- Backport missing macros of directory paths from upstream
+ %_environmentdir
+ %_modulesloaddir
+ %_modprobedir

- Make sure %_restart_on_update_never and %_stop_on_removal_never don't expand to the
empty string. (bsc#1176932)
Otherwise sequences like the following code:
if [ ... ]; then
%_restart_on_update_never
fi
would result in the following incorrect shell syntax:
if [ ... ]; then
fi

This update was imported from the SUSE:SLE-15:Update update project.