Multiple sources are hosted on OpenWrts source server only. The source
URLs to point to the server vary based on different epochs in OpenWrts
history.
Replace all by @OPENWRT which is an "empty" mirror, therefore using the
fallback servers sources.cdn.openwrt.org and sources.openwrt.org.
Signed-off-by: Paul Spooren <mail@aparcar.org>
0bc6a69776