Fix for KMP_AFFINITY=disabled and KMP_TOPOLOGY_METHOD=hwloc

With these settings, the create_hwloc_map() method was being called causing an
assert(). After some consideration, it was determined that disabling affinity
explicitly should just disable hwloc as well. i.e., KMP_AFFINITY overrides
KMP_TOPOLOGY_METHOD. This lets the user know that the Hwloc mechanism is being
ignored when KMP_AFFINITY=disabled.

Differential Revision: https://reviews.llvm.org/D33208

llvm-svn: 304344