Add --tcp option to dstat command for connection stats
Add --tcp option to dstat command for connection stats

This enables tcp stats (listen, established, syn, time_wait, close) in
dstat to allow us to get a high-level view of performance changes in
the system during gate runs.

Change-Id: Ifbffbed22446e7e6a3b825c18266b63d2f2e7718

nawawi/openstack,group-policy/devstack,openstack-dev/devstack,dtroyer/devstack,richliu/devstack,richliu/devstack,noironetworks/devstack,openstack-dev/devstack,group-policy/devstack,nawawi/openstack,noironetworks/devstack,dtroyer/devstack