Do not close connections on tcpdump nodes

Do not close connections on tcpdump nodes

there is some hard to nail down bug in the test code
such that closing a single tcpdump connection is
actually closing a different one and when that different
one is attempted to be used, we fail on connection
not found. Until that is figured out, this should
work around that. Every suite that uses this tcpdump
functionality will have a suite teardown that uses
close all connections which should eventually close
these

Change-Id: Iae448ee8935589aaebb111832b6ae1e9055e70f3
Signed-off-by: Jamo Luhrsen <jluhrsen@redhat.com>