openwrt-keyring: Only copy sign key for snapshots

Instead of adding all public signature keys from the openwrt-keyring
repository only add the key which is used to sign the master feeds.

If one of the other keys would be compromised this would not affect
users of master snapshot builds.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

package/system/openwrt-keyring/Makefile

@@ -3,7 +3,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=openwrt-keyring
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/keyring.git
@@ -32,7 +32,8 @@ Build/Compile=
 
 define Package/openwrt-keyring/install
 	$(INSTALL_DIR) $(1)/etc/opkg/keys/
-	$(INSTALL_DATA) $(PKG_BUILD_DIR)/usign/* $(1)/etc/opkg/keys/
+	# Public usign key for unattended snapshot builds
+	$(INSTALL_DATA) $(PKG_BUILD_DIR)/usign/b5043e70f9a75cde $(1)/etc/opkg/keys/
 endef
 
 $(eval $(call BuildPackage,openwrt-keyring))