system mpi libpath can preempt ThirdParty location

assigned to @mark

@andy

The problem is actually stranger than originally thought.

1. ldd -v /path/to/bin/snappyHexMesh | grep libscotch
   shows that our ThirdParty libscotch is being used.
2. mpirun -np 1 ldd -v /path/to/bin/snappyHexMesh | grep libscotch
   shows that /usr/lib64/mpi/gcc/openmpi2/lib64/libscotch.so is being used.

This will not be any different for libptscotch, so it looks like we always run the risk of ill-defined behaviour when there is an MPI system version of thirdparty software!

mentioned in commit bf1ed94e

mentioned in commit f89fb3e0

closed