sysmocom-openvpn-config: Always start but rename the config file

For the sysmoBTS (and other devices) we always enable the service
but move the config file to a name that will be ignored by the
systemd generator.

recipes-config/sysmocom-openvpn-config/sysmocom-openvpn-config_1.bb

@@ -7,10 +7,19 @@ LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384
 SRC_URI = "file://sysmocom-vpn.conf"
 PR = "r4"
 
-CONFFILES_${PN} = "${sysconfdir}/openvpn/sysmocom-vpn.conf"
+CONFFILES_${PN} = "${sysconfdir}/openvpn/sysmocom-vpn.conf.off"
 PACKAGE_ARCH = "all"
 
 do_install() {
 	install -d ${D}${sysconfdir}/openvpn
-	install -m 0644 ${WORKDIR}/sysmocom-vpn.conf ${D}${sysconfdir}/openvpn
+	install -m 0644 ${WORKDIR}/sysmocom-vpn.conf ${D}${sysconfdir}/openvpn/sysmocom-vpn.conf.off
+}
+
+# Always enable the OpenVPN service. This assumes that
+# this package will never be inside the nornal sysmocom
+# feed.
+FILES_${PN} += "${systemd_unitdir}"
+do_install_append() {
+	install -d ${D}${systemd_unitdir}/system/multi-user.target.wants/
+	ln -sf ../openvpn.service ${D}${systemd_unitdir}/system/multi-user.target.wants/
 }