NEST Topology crashes for fixed fan-out on multiple MPI processes

[heplesser]

The following code will work correctly if run on a single MPI process, but crashes reporting an IllegalConnection in ConnectLayers_i_i_D when run on two or more processes:

/layer << /rows 3 /columns 3 /elements /iaf_neuron >> CreateLayer def
layer layer << /connection_type /divergent /number_of_connections 1 >> ConnectLayers

The code works fine for /convergent connections and also if a connection probability is given instead of a fixed number of outgoing connections.