fix unittests failures due to py3

fix unittests failures due to py3

Traceback (most recent call last):
  File "/home/jenkins/opnfv/slave_root/workspace/yardstick-verify-master/tests/unit/network_services/vnf_generic/vnf/test_vpe_vnf.py", line 306, in test_instantiate
    self.context_cfg))
AssertionError: 0 != None

Traceback (most recent call last):
  File "/home/jenkins/opnfv/slave_root/workspace/yardstick-verify-master/tests/unit/network_services/vnf_generic/vnf/test_base.py", line 55, in test_clear
    self.assertEqual(queue_file_wrapper.q_out.empty(), True)
  File "/usr/lib/python3.5/unittest/case.py", line 820, in assertEqual
    assertion_func(first, second, msg=msg)
  File "/usr/lib/python3.5/unittest/case.py", line 813, in _baseAssertEqual
    raise self.failureException(msg)
AssertionError: False != True

Traceback (most recent call last):
  File "/home/jenkins/opnfv/slave_root/workspace/yardstick-verify-master/tests/unit/network_services/vnf_generic/vnf/test_tg_trex.py", line 321, in test_run_traffic
    self.assertEqual(True, result)
  File "/usr/lib/python3.5/unittest/case.py", line 820, in assertEqual
    assertion_func(first, second, msg=msg)
  File "/usr/lib/python3.5/unittest/case.py", line 813, in _baseAssertEqual
    raise self.failureException(msg)
AssertionError: True != False

Traceback (most recent call last):
  File "/home/jenkins/opnfv/slave_root/workspace/yardstick-verify-master/tests/unit/network_services/vnf_generic/vnf/test_tg_rfc2544_trex.py", line 369, in test_run_traffic
    self.assertEqual(True, result)
  File "/usr/lib/python3.5/unittest/case.py", line 820, in assertEqual\
    assertion_func(first, second, msg=msg)
  File "/usr/lib/python3.5/unittest/case.py", line 813, in _baseAssertEqual\
    raise self.failureException(msg)
AssertionError: True != False

Change-Id: I68340196b8cc9f0fc2e4e0ef1022e8098fc860f0
Signed-off-by: Deepak S <deepak.s@linux.intel.com>