Occasional failure of test_model_flavors.test_group for dpd datatype

[fritzo]

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FAIL: distributions.tests.test_model_flavors.test_group('dpd',)
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Traceback (most recent call last):
  File "/home/ubuntu/.virtualenvs/sf/local/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/home/ubuntu/sf/distributions/distributions/tests/test_model_flavors.py", line 86, in _test_group
    shared.add_value(value)
  File "/home/ubuntu/sf/distributions/distributions/dbg/models/dpd.py", line 138, in add_value
    assert value != OTHER, 'cannot add OTHER'
AssertionError: cannot add OTHER