Fix filter_updater test_update with MPI
Fix filter_updater test_update with MPI

The indices to change types to check for group updating used
state.N_particles which is the global number of particles leading to
out of bounds errors in indexing a MPI local array. Use Np which stores
the rank local number of particles now.

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