TST: uncaught warning in min/max localize

[jreback]

@jbrockmendel

=============================================================================================================================== warnings summary ================================================================================================================================
pandas/tests/scalar/timestamp/test_timezones.py::TestTimestampTZOperations::()::test_tz_localize_pushes_out_of_bounds
  /Users/jreback/pandas/pandas/tests/scalar/timestamp/test_timezones.py:32: RuntimeWarning: overflow encountered in long_scalars
    Timestamp.min.tz_localize('Asia/Tokyo')
  /Users/jreback/pandas/pandas/tests/scalar/timestamp/test_timezones.py:39: RuntimeWarning: overflow encountered in long_scalars
    Timestamp.max.tz_localize('US/Pacific')

-- Docs: http://doc.pytest.org/en/latest/warnings.html
==================================================================================================================== 435 passed, 2 warnings in 2.29 seconds =====================================================================================================================