openvpn: use correct step override method

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/openvpn/openvpn.mk

@@ -26,20 +26,18 @@ else
 	OPENVPN_CONF_OPT += --disable-crypto --disable-ssl
 endif
 
-$(eval $(call AUTOTARGETS,package,openvpn))
-
-$(OPENVPN_TARGET_INSTALL_TARGET):
-	$(call MESSAGE,"Installing")
-	$(INSTALL) -m 755 $(OPENVPN_DIR)/openvpn \
+define OPENVPN_INSTALL_TARGET_CMDS
+	$(INSTALL) -m 755 $(@D)/openvpn \
 		$(TARGET_DIR)/usr/sbin/openvpn
 	if [ ! -f $(TARGET_DIR)/etc/init.d/openvpn ]; then \
 		$(INSTALL) -m 755 -D package/openvpn/openvpn.init \
 			$(TARGET_DIR)/etc/init.d/openvpn; \
 	fi
-	touch $@
+endef
 
-$(OPENVPN_TARGET_UNINSTALL):
-	$(call MESSAGE,"Uninstalling")
+define OPENVPN_UNINSTALL_TARGET_CMDS
 	rm -f $(TARGET_DIR)/usr/sbin/openvpn
 	rm -f $(TARGET_DIR)/etc/init.d/openvpn
-	rm -f $(OPENVPN_TARGET_INSTALL_TARGET) $(OPENVPN_HOOK_POST_INSTALL)
+endef
+
+$(eval $(call AUTOTARGETS,package,openvpn))