bugfix: Trafficgen Ixia does not work

bugfix: Trafficgen Ixia does not work

IXIA traffic generator can be controlled by two different
VSPERF's wrappers IxNet (preferred) and Ixia (legacy and
outdated). It has been found, that Ixia wrapper can't be used
because of missing "packetsize" traffic item. Also only
IXIA OS 6.60 was supported and never IXIA OS versions
were not working. Both limitations were fixed.
Also reported results were fixed to show correct values
for MBPS items.

JIRA: VSPERF-417

Change-Id: I191aa9fee2683877ce373b6aa7cd1c72e9847568
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: Bill Michalowski <bmichalo@redhat.com>
Reviewed-by: Christo Kleu <christo.kleu@netronome.com>