ovsdpdk: Custom Statistics Tests

ovsdpdk: Custom Statistics Tests

Functional testcases for the validation of Custom Statistics support
by OVS. The Custom Statistics feature allows Custom Statistics to be
accessed by VSPERF.
These statistics include for example rx_missed_errors, rx_errors,
tx_errors, rx_mbuf_allocation_errors, rx_crc_errors.
These testcases require DPDK v17.11, the latest Open vSwitch(v2.9.90)
and the IxNet traffic-generator.

JIRA: VSPERF-572

Change-Id: I30cbe6067d6bdd0fc2a262b86f306b66a77d085f
Signed-off-by: Richard Elias <richardx.elias@intel.com>
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>