fix linker problems

Some variables were not assigned values in the constructor.  This caused an "MPI_ERR_COMM: invalid communicator" error when using multiple gpus.

In copyEdgeNodes the nodes were copied to the wrong places of the send vector. The problem was that the full vector sendProcessNeighborHostAllNodes was used for copying instead of the shorter vector sendProcessNeighborHostAfterFtoC

Only copy send nodes which are not part of the reduced communication (for reduced comm after fine to coarse)

(cherry picked from commit 520f1db1)