iperf: used an updated renamed tarball instead of main upstream URL

iperf upstream added some bugfixes to the already released 2.0.9 version
without changing the filename. This conflicts with old mirrored files
and the hash that we previously used.
To avoid conflict, use a renamed tarball from mirror2.openwrt.org
containing the new upstream changes

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/network/utils/iperf/Makefile

@@ -9,11 +9,16 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=iperf
 PKG_VERSION:=2.0.9
+PKG_VERSION_SUFFIX:=a
 PKG_RELEASE:=1
 
-PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
-PKG_SOURCE_URL:=@SF/iperf2
-PKG_MD5SUM:=1bb3a1d98b1973aee6e8f171933c0f61
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)$(PKG_VERSION_SUFFIX).tar.gz
+# Temporary URL change - iperf upstream altered the already released target
+# without bumping the version number. The new tarball is renamed to avoid
+# conflicts with existing mirrored files.
+# PKG_SOURCE_URL:=@SF/iperf2
+PKG_SOURCE_URL:=http://mirror2.openwrt.org/sources
+PKG_MD5SUM:=db02911f35686e808ed247160dfa766e08ae3f59d1e7dcedef0ffb2a6643f0bf
 
 PKG_MAINTAINER:=Felix Fietkau <nbd@nbd.name>
 PKG_LICENSE:=BSD-3-Clause