Fix/mpi info

This branch was intended to fix an mpiInfo error in taurus.

It cleans up the mpiInfo cmake file and fixes a minor bug introduced by 8e4609e06ef258cb08a646e665131e65b26cd3b5 in PIConGPU's CMakeList.

Furthermore, it introduces a work-around for a weird behaviour of bullxmpi when compiled with c++ bindings enabled.