Remove old OpenWrt packages feeds, as they were there just for netperf

feeds.conf

 # This is a feeds.conf template used by qMpFW (http://qmp.cat/projects/qmpfw)
 
-#src-link openwrt_packages PATH/packages
 src-link qmp PATH/qmp/packages
 src-git libremap_agent https://github.com/libremap/libremap-agent-openwrt.git
 src-git b6m git://qmp.cat/b6m.git;openwrt
 src-git nc git://qmp.cat/ncr.git
-src-git oldpackages_trunk http://git.openwrt.org/packages.git
-src-git oldpackages_14_07 http://git.openwrt.org/14.07/packages.git