xfail test_cross_engine_read_write_netcdf3 (#2051)
xfail test_cross_engine_read_write_netcdf3 (#2051)

This should fix the test suite on Travis-CI again.
pydata/xarray,shoyer/xarray,markelg/xray,jhamman/xarray,markelg/xray,chunweiyuan/xarray,pydata/xarray,markelg/xray,jhamman/xarray,jhamman/xarray,jhamman/xray,shoyer/xarray,pydata/xarray,jcmgray/xarray,shoyer/xray,xray/xray