etesync-server: Minor Makefile cleanup

* Replace creating an empty PYTHON3_PKG_DIR with setting filespec to an
  empty value

* Disable the default Python package build recipe (with
  PYTHON3_PKG_BUILD:=0) and set an empty Build/Compile

* Remove VARIANT:=python3 and PROVIDES (providing the same name as the
  package)

* Add PKG_BUILD_PARALLEL:=1

Signed-off-by: Jeffery To <jeffery.to@gmail.com>

net/etesync-server/Makefile

@@ -2,7 +2,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=etesync-server
 PKG_VERSION:=0.3.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=etesync-server-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://github.com/etesync/server/archive/v$(PKG_VERSION)
@@ -12,16 +12,14 @@ PKG_LICENSE:=AGPL-3.0-only
 PKG_LICENSE_FILES:=LICENSE
 PKG_MAINTAINER:=Peter Stadler <peter.stadler@student.uibk.ac.at>
 
+PKG_BUILD_PARALLEL:=1
+PYTHON3_PKG_BUILD:=0
+
 PKG_UNPACK=$(HOST_TAR) -C $(PKG_BUILD_DIR) --strip-components=1 -xzf $(DL_DIR)/$(PKG_SOURCE)
 
 include $(INCLUDE_DIR)/package.mk
 include ../../lang/python/python3-package.mk
 
-# this allows using python3-package.mk with a non-package app (etesync-server):
-define Py3Build/Compile
-	$(INSTALL_DIR) $(PKG_INSTALL_DIR)/$(PYTHON3_PKG_DIR)
-endef
-
 
 define Package/etesync-server
 	SECTION:=net
@@ -34,8 +32,6 @@ define Package/etesync-server
 		+python3-django-cors-headers +python3-django-etesync-journal \
 		+uwsgi +uwsgi-python3-plugin +uwsgi-syslog-plugin
 	USERID:=etesync=44312
-	VARIANT:=python3
-	PROVIDES:=etesync-server
 endef
 
 
@@ -44,6 +40,9 @@ define Package/etesync-server/description
 endef
 
 
+Build/Compile:=:
+
+
 define Py3Package/etesync-server/install
 	$(INSTALL_DIR) $(1)/www/etesync/static/
 
@@ -83,6 +82,8 @@ define Py3Package/etesync-server/install
 	$(INSTALL_BIN) ./files/uwsgi.init $(1)/etc/init.d/etesync-server
 endef
 
+Py3Package/etesync-server/filespec:=
+
 
 define Package/etesync-server/postrm
 #!/bin/sh