rpm: better systemd integration

- Suse wants units in /usr/lib/systemd/system
- respect system-preset

Makefile

 DESTDIR = /
 PREFIX = /usr/local
 MANDIR = $(PREFIX)/share/man
+UNITDIR = /lib/systemd/system
 
 MANPAGELIST := $(patsubst %,docs/%,re6st-conf.1 re6st-registry.1 re6stnet.8)
 NM = /etc/NetworkManager/dispatcher.d/50re6stnet
@@ -12,7 +13,7 @@ all: $(MANPAGELIST)
 
 install: install-noinit
 	for x in daemon/*.service; \
-	do install -Dpm 0644 $$x $(DESTDIR)/lib/systemd/system/$${x##*/}; \
+	do install -Dpm 0644 $$x $(DESTDIR)$(UNITDIR)/$${x##*/}; \
 	done
 
 install-noinit: install-man

re6stnet.spec

 %define _builddir %(pwd)
 %define ver %(python re6st/version.py)
+%define units re6stnet.service re6st-registry.service
 
 Summary:    resilient, scalable, IPv6 network application
 Name:       re6stnet
@@ -25,7 +26,7 @@ make
 
 %install
 set $RPM_BUILD_ROOT
-make install PREFIX=%_prefix MANDIR=%_mandir DESTDIR=$1
+make install PREFIX=%_prefix MANDIR=%_mandir DESTDIR=$1 %{?_unitdir:UNITDIR=%{_unitdir}}
 # Exclude man pages because they will be compressed.
 find $1 -mindepth 1 -path \*%_mandir -prune -o \
   -name re6st\* -prune -printf /%%P\\n > INSTALLED
@@ -39,18 +40,17 @@ rm -rf "$RPM_BUILD_ROOT" INSTALLED
 
 %post
 if [ $1 -eq 1 ]; then
-    /bin/systemctl enable re6stnet.service re6st-registry.service || :
+    /bin/systemctl preset %{units} || :
 fi >/dev/null 2>&1
 
 %preun
 if [ $1 -eq 0 ]; then
-    /bin/systemctl --no-reload disable re6stnet.service re6st-registry.service || :
-    /bin/systemctl stop re6stnet.service re6st-registry.service || :
+    /bin/systemctl --no-reload disable %{units} || :
+    /bin/systemctl stop %{units} || :
 fi >/dev/null 2>&1
 
 %postun
 /bin/systemctl daemon-reload >/dev/null 2>&1 || :
-if [ $1 -ge 1 ] ; then
-    # only try to restart the registry (doing same for re6stnet could be troublesome)
-    /bin/systemctl try-restart re6st-registry.service >/dev/null 2>&1 || :
+if [ $1 -ge 1 ]; then
+    /bin/systemctl try-restart %{units} >/dev/null 2>&1 || :
 fi