gnunet: fix breakage caused by previous commit

keep.d has to exist as well...

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

net/gnunet/Makefile

@@ -162,8 +162,9 @@ define Package/gnunet/install
 	done )
 
 	$(INSTALL_DATA) $(PKG_INSTALL_DIR)/usr/share/gnunet/hellos/* $(1)/usr/share/gnunet/hellos
-	$(INSTALL_DIR) $(1)/etc/init.d/
+	$(INSTALL_DIR) $(1)/etc/init.d
 	$(INSTALL_BIN) ./files/gnunet.init $(1)/etc/init.d/gnunet
+	$(INSTALL_DIR) $(1)/lib/upgrade/keep.d
 	$(INSTALL_DATA) ./files/gnunet.upgrade $(1)/lib/upgrade/keep.d/gnunet
 endef