runfullday.sh: don't hardcode 10Gbit/s speed
runfullday.sh: don't hardcode 10Gbit/s speed

(but still compare L3 results with line rate at 10Gbit/s using 256 Bytes/frame)

while at it, fix the following minor issues:
 - use mkdir -p to avoid (harmless) errors when the test is run multiple times
   on the same host
 - fix mis-spelled 'throughput'

chaudron/ovs_perf,chaudron/ovs_perf