CA-103508: Fixing DHCP client configuration and threshold creation

This pull request carries fixes for two problems:
   * dhclient, when run on multiple interfaces interferes (leases/pids)
   * The threshold limit for gating over transmission was not determined in relation to the amount of data being communicated.

The second of the above issues turned out to be more important because sometimes, many packets are re-transmitted. We could consider this something to look into, except for the fact that we are not traffic flows just associated to the iperf session (we don't have that level of granularity). For the moment, the approach is to instead have a warning level, and an error level.