open-plc-utils: cleanup package meta-data

Align package variables to other packages which also use a git checkout
as tarball:
 - PKG_VERSION should not be set to a date, just rely on package default
   handling which apply automatically when using PKG_SOURCE_VERSION
 - introduce a plain PKG_RELEASE instead to allow keeping track of modified packaging
 - PKG_SOURCE_DIR is set by package defaults
 - same for PKG_SOURCE
 - this results in a different hash of the tarball created, so adjust
   PKG_MIRROR_HASH

Signed-off-by: Michael Heimpold <mhei@heimpold.de>

utils/open-plc-utils/Makefile

@@ -8,15 +8,12 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=open-plc-utils
-PKG_VERSION:=2018-11-03
-PKG_RELEASE:=$(PKG_SOURCE_VERSION)
+PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL:=https://github.com/qca/open-plc-utils.git
-PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
 PKG_SOURCE_VERSION:=32408520fcebe785983a68e39ec83830a3005779
-PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)-$(PKG_SOURCE_VERSION).tar.xz
-PKG_MIRROR_HASH:=1c5a2bb75550f1d7069f857c30f1f45ccfd3b0b0e9abadbca10f4df582f51d1c
+PKG_MIRROR_HASH:=b5ae48fd300f75b948a2b2a5f6cd4465b7a336495685f73100ad33a5d43a4c05
 
 PKG_MAINTAINER:=Florian Fainelli <florian@openwrt.org>