Bugfix: network_utilization: parse error

Bugfix: network_utilization: parse error

JIRA: YARDSTICK-586

When run tc072, there is a bug: network_utilization: parse error, see the log:
ERROR ('network_utilization: parse error', [], [u'05:10:46', u'IFACE',
        u'rxpck/s', u'txpck/s', u'rxkB/s', u'txkB/s', u'rxcmp/s',
        u'txcmp/s', u'rxmcst/s', u'%ifutil'])
Traceback (most recent call last):
    File
    "/usr/local/lib/python2.7/dist-packages/yardstick/benchmark/runners/duration.py",
    line 69, in _worker_process
    method(data)
    File
    "/usr/local/lib/python2.7/dist-packages/yardstick/benchmark/scenarios/networking/netutilization.py",
    line 191, in run
    result.update(self._get_network_utilization())
    File
    "/usr/local/lib/python2.7/dist-packages/yardstick/benchmark/scenarios/networking/netutilization.py",
    line 182, in _get_network_utilization
    result = self._filtrate_result(raw_result)
    File
    "/usr/local/lib/python2.7/dist-packages/yardstick/benchmark/scenarios/networking/netutilization.py",
    line 146, in _filtrate_result
    fields, line)
    RuntimeError: ('network_utilization: parse error', [], [u'05:10:46',
            u'IFACE', u'rxpck/s', u'txpck/s', u'rxkB/s', u'txkB/s',
            u'rxcmp/s', u'txcmp/s', u'rxmcst/s', u'%ifutil'])

Maybe the tool has some changes.

Change-Id: I6c4fe3fe9f749ec942fb5fbd799b8f4ab9a5c16c
Signed-off-by: chenjiankun <chenjiankun1@huawei.com>