CONFIG: revert to openmpi-1.10.4

- this is the same version as OpenFOAM-1612 shipped with and seems to
  have fewer issues than the newer openmpi-2.1.1

etc/config.csh/mpi

@@ -49,7 +49,7 @@ case SYSTEMOPENMPI:
     breaksw
 
 case OPENMPI:
-    setenv FOAM_MPI openmpi-2.1.1
+    setenv FOAM_MPI openmpi-1.10.4
     _foamEtc config.csh/openmpi                 # <- Adjustments (optional)
 
     setenv MPI_ARCH_PATH $WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$FOAM_MPI

etc/config.sh/mpi

@@ -55,7 +55,7 @@ SYSTEMOPENMPI)
     ;;
 
 OPENMPI)
-    export FOAM_MPI=openmpi-2.1.1
+    export FOAM_MPI=openmpi-1.10.4
     _foamEtc config.sh/openmpi                  # <- Adjustments (optional)
 
     export MPI_ARCH_PATH=$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$FOAM_MPI