network/netperf: Mirror download url.
network/netperf: Mirror download url.

Signed-off-by: Matteo Bernardini <638c89fd48409d8ef3e3a3c9b0a27af8629fef36@slackbuilds.org>

panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds