Reused server installation in client target

Makefile

-all: strongswan-conf swanctl-conf ipsec-notify
+all: server
+
+server: strongswan-conf swanctl-conf ipsec-notify
 	tar xf strongswan-5.8.0.tar.bz2
 	cd strongswan-5.8.0 && ./configure --prefix=/usr --sysconfdir=/etc --enable-systemd --enable-swanctl --disable-charon --disable-stroke --disable-scepclient --disable-connmark --enable-curl
 	$(MAKE) -C strongswan-5.8.0
@@ -12,21 +14,9 @@ all: strongswan-conf swanctl-conf ipsec-notify
 	chmod 755 /usr/sbin/ipsec-notify.sh
 	rm -rf strongswan-5.8.0
 
-client: strongswan-conf swanctl-conf ipsec-notify vpn-config
-	tar xf strongswan-5.8.0.tar.bz2
-	cd strongswan-5.8.0 && ./configure --prefix=/usr --sysconfdir=/etc --enable-systemd --enable-swanctl --disable-charon --disable-stroke --disable-scepclient --disable-connmark --enable-curl
-	$(MAKE) -C strongswan-5.8.0
-# FIXME: strongswan tests failure!
-	-$(MAKE) -C strongswan-5.8.0 check
-	$(MAKE) -C strongswan-5.8.0 install
-	systemctl enable strongswan
-	@echo "$$STRONGSWAN_CONF" > /etc/strongswan.conf
-	@echo "$$SWANCTL_CONF" > /etc/swanctl/swanctl.conf
-	@echo "$$IPSEC_NOTIFY" > /usr/sbin/ipsec-notify.sh
-	chmod 755 /usr/sbin/ipsec-notify.sh
+client: server vpn-config
 	install -v -Dm755 vpn /usr/share/easycwmp/functions/vpn
 	@echo "$$VPN_CONFIG" > /etc/config/vpn
-	rm -rf strongswan-5.8.0
 
 strongswan-conf:
 define STRONGSWAN_CONF