strongswan: correctly install plugin include configs

Signed-off-by: Steven Barth <steven@midlink.org>

net/strongswan/Makefile

 
 PKG_NAME:=strongswan
 PKG_VERSION:=5.2.1
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=http://download.strongswan.org/ http://download2.strongswan.org/
     DEPENDS:= +strongswan $(3)
   endef
 
-  strongswan_mod_conf=$(wildcard $(PKG_INSTALL_DIR)/etc/strongswan.d/charon/$(1).conf)
   define Package/strongswan-mod-$(1)/install
 	$(INSTALL_DIR) $$(1)/etc/strongswan.d/charon
-	$(if $(call strongswan_mod_conf,$(1)), \
-		$(INSTALL_DATA) \
-			$(call strongswan_mod_conf,$(1)) \
-			$$(1)/etc/strongswan.d/charon/ \
-	)
+	if [ -f $(PKG_INSTALL_DIR)/etc/strongswan.d/charon/$(1).conf ]; then \
+		$(INSTALL_DATA) $(PKG_INSTALL_DIR)/etc/strongswan.d/charon/$(1).conf $$(1)/etc/strongswan.d/charon/; fi
 	$(INSTALL_DIR) $$(1)/usr/lib/ipsec/plugins
 	$(CP) $(PKG_INSTALL_DIR)/usr/lib/ipsec/plugins/libstrongswan-$(1).so \
 		$$(1)/usr/lib/ipsec/plugins/
 	$(call Plugin/$(1)/install,$$(1))
   endef
 
-  Package/strongswan-mod-$(1)/conffiles=$(patsubst $(PKG_INSTALL_DIR)%,%,$(call strongswan_mod_conf,$(1)))
-
   $$(eval $$(call BuildPackage,strongswan-mod-$(1)))
 endef