Here is a list of files that are known to be shared by both packages (according to the Contents file for sid/amd64, which may be slightly out of sync):
/usr/lib/libmpi_cxx.so.1 /usr/lib/libmpi_f77.so.1 /usr/lib/libmpi_f77.so.1.0.7 /usr/lib/libmpi_f90.so.1 /usr/lib/libmpi_f90.so.1.3.0 /usr/lib/libompitrace.so.0 /usr/lib/libompitrace.so.0.0.0 /usr/lib/openmpi/lib/libompitrace.so.0.0.0 /usr/lib/openmpi/lib/mpi.mod /usr/lib/openmpi/lib/openmpi/libompi_dbg_msgq.so /usr/lib/openmpi/lib/openmpi/mca_allocator_basic.so /usr/lib/openmpi/lib/openmpi/mca_allocator_bucket.so /usr/lib/openmpi/lib/openmpi/mca_bml_r2.so /usr/lib/openmpi/lib/openmpi/mca_btl_openib.so /usr/lib/openmpi/lib/openmpi/mca_btl_self.so /usr/lib/openmpi/lib/openmpi/mca_btl_sm.so /usr/lib/openmpi/lib/openmpi/mca_btl_tcp.so /usr/lib/openmpi/lib/openmpi/mca_coll_basic.so /usr/lib/openmpi/lib/openmpi/mca_coll_hierarch.so /usr/lib/openmpi/lib/openmpi/mca_coll_inter.so /usr/lib/openmpi/lib/openmpi/mca_coll_self.so /usr/lib/openmpi/lib/openmpi/mca_coll_sm.so /usr/lib/openmpi/lib/openmpi/mca_coll_tuned.so /usr/lib/openmpi/lib/openmpi/mca_crs_none.so /usr/lib/openmpi/lib/openmpi/mca_dpm_orte.so /usr/lib/openmpi/lib/openmpi/mca_ess_env.so /usr/lib/openmpi/lib/openmpi/mca_ess_hnp.so /usr/lib/openmpi/lib/openmpi/mca_ess_singleton.so /usr/lib/openmpi/lib/openmpi/mca_ess_slurm.so /usr/lib/openmpi/lib/openmpi/mca_ess_tool.so /usr/lib/openmpi/lib/openmpi/mca_grpcomm_bad.so /usr/lib/openmpi/lib/openmpi/mca_io_romio.so /usr/lib/openmpi/lib/openmpi/mca_iof_hnp.so /usr/lib/openmpi/lib/openmpi/mca_iof_orted.so /usr/lib/openmpi/lib/openmpi/mca_iof_tool.so /usr/lib/openmpi/lib/openmpi/mca_mpool_sm.so /usr/lib/openmpi/lib/openmpi/mca_odls_default.so /usr/lib/openmpi/lib/openmpi/mca_oob_tcp.so /usr/lib/openmpi/lib/openmpi/mca_osc_pt2pt.so /usr/lib/openmpi/lib/openmpi/mca_plm_rsh.so /usr/lib/openmpi/lib/openmpi/mca_plm_slurm.so /usr/lib/openmpi/lib/openmpi/mca_pml_bfo.so /usr/lib/openmpi/lib/openmpi/mca_pml_cm.so /usr/lib/openmpi/lib/openmpi/mca_pml_ob1.so /usr/lib/openmpi/lib/openmpi/mca_pstat_linux.so /usr/lib/openmpi/lib/openmpi/mca_pubsub_orte.so /usr/lib/openmpi/lib/openmpi/mca_ras_gridengine.so /usr/lib/openmpi/lib/openmpi/mca_ras_loadleveler.so /usr/lib/openmpi/lib/openmpi/mca_ras_slurm.so /usr/lib/openmpi/lib/openmpi/mca_rcache_vma.so /usr/lib/openmpi/lib/openmpi/mca_rmaps_rank_file.so /usr/lib/openmpi/lib/openmpi/mca_rmaps_resilient.so /usr/lib/openmpi/lib/openmpi/mca_rmaps_round_robin.so /usr/lib/openmpi/lib/openmpi/mca_rmaps_seq.so /usr/lib/openmpi/lib/openmpi/mca_rml_oob.so /usr/lib/openmpi/lib/openmpi/mca_routed_binomial.so /usr/lib/openmpi/lib/openmpi/mca_routed_direct.so /usr/lib/openmpi/lib/openmpi/mca_routed_radix.so /usr/lib/openmpi/lib/openmpi/mca_shmem_mmap.so /usr/lib/openmpi/lib/openmpi/mca_shmem_posix.so /usr/lib/openmpi/lib/openmpi/mca_shmem_sysv.so /usr/lib/openmpi/lib/openmpi/mca_vprotocol_pessimist.so -Ralf.
