Tests: remote_test.py. Private member test catching dunder names.

Tests: remote_test.py.  Private member test catching dunder names.

Private member check also catches __iter__, since it starts with '_'.

Fixes:
  Captured traceback:
  ~~~~~~~~~~~~~~~~~~
      b'Traceback (most recent call last):'
      b'  File "/vpp/test/test_memif.py", line 47, in tearDown'
      b'    remove_all_memif_vpp_config(self.remote_test)'
      b'  File "/vpp/test/vpp_memif.py", line 36, in remove_all_memif_vpp_config'
      b'    for d in dump:'
      b"TypeError: 'SerializableClassCopy' object is not iterable"
      b''

Change-Id: I6a3f3e0f2b1b2d0a2b97faa23bf542ff8f92de43
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>