karaf - ${karaf.home}/etc should use ${karaf.etc} in etc configs

File org.apache.karaf.features.cfg under "karaf/etc" uses eg.

featuresRepositories = file:${karaf.home}/etc/a8633ad5-8d0c-4bbf-9b53-705447bb4874.xml

which should rather use ${karaf.etc} placeholder, because if user uses KARAF_ETC="some-other-place" it will not work.