etc/bashrc, etc/config.sh:

- "$FOAM_USER_APPBIN" and "$FOAM_USER_LIBBIN" have been added to
    "foamOldDirs" in "etc/bashrc" and "etc/config.sh/unset"

  - "$OPAL_PREFIX" is now undefined in the option "SYSTEMOPENMPI" within
    "etc/config.sh/mpi", but only if the path defined in this variable
    is cleaned when using "foamCleanPath".

  - "$OPAL_PREFIX" is now also conditionally undefined in
    "etc/config.sh/unset" when the path is picked up by "foamCleanPath".

Patch contributed by Bruno Santos
Resolved bug-report http://bugs.openfoam.org/view.php?id=2210

etc/config.sh/mpi

@@ -37,6 +37,12 @@ SYSTEMOPENMPI)
     # Use the system installed openmpi, get library directory via mpicc
     export FOAM_MPI=openmpi-system
 
+    # Undefine OPAL_PREFIX if set to one of the paths on foamOldDirs
+    if [ -z "$($foamClean "$OPAL_PREFIX" "$foamOldDirs")" ]
+    then
+        unset OPAL_PREFIX
+    fi
+
     libDir=`mpicc --showme:link | sed -e 's/.*-L\([^ ]*\).*/\1/'`
 
     # Bit of a hack: strip off 'lib' and hope this is the path to openmpi