ovs_performance.py: Fixed --warm-up command for use with TC
ovs_performance.py: Fixed --warm-up command for use with TC

Using the --warm-up command was broken for the TC datapath.
This was introduced in commit: 3fa7b6f0cd8250a96bc536489fa43142378af6d3

chaudron/ovs_perf,chaudron/ovs_perf