Fixed a bug where the neighbor list unit test was failing
Fixed a bug where the neighbor list unit test was failing

NeighborList has gotten smarter and does not allow rigidi body exclusions when there are no bodies in the system. The nlist unit test failed to initialize bodies which triggered a failure in the test. This problem has been resolved.

joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue