Split the netperf run script into 3 ones so that it can be used more easily
in an automated run.
It is solely for foc_arndale by now.
l4linux_netperf.run - use nic via usb2.0
l4linux_netperf-usb30.run - use nic via usb3.0
l4linux_netperf-bridge.run - use nic via usb3.0 + bridge
* Always download md5sum file and check downloaded binaries
* Extend sleep time in l4linux_netperf script, so that DHCP has enough time
* Fix regexp rule in l4linux_netperf run script to work with MAC addresses
containing only numbers
Fix#787