trafficgen: Postponed call of connect()

trafficgen: Postponed call of connect()

In order to support execution of SW traffic generator inside VM,
we have to postpone the call of connect() method from traffic controller.
Currently it is called during initialization phase, when VMs are not
active and thus connect() would always fail. This patch moves the call
of connect() inside configure() method, which is called later when VMs
are up and running.
This modification allows to configure VM to VM scenario, where 1st VM is
running a loopback application and 2nd one executes one of supported SW
traffic generators, i.e. T-Rex or MoonGen.

Change-Id: Ifeb659aadaa2e1cd5975564965e1719c1e72a12e
Signed-off-by: Martin Klozik <martinx.klozik@intel.com>
Reviewed-by: Al Morton <acmorton@att.com>
Reviewed-by: Christian Trautman <ctrautma@redhat.com>
Reviewed-by: Sridhar Rao <sridhar.rao@spirent.com>
Reviewed-by: Trevor Cooper <trevor.cooper@intel.com>