Per a prior commit, the presence of "hwloc.h" can cause ambiguity when
using --with-hwloc=external (i.e., whether to include
opal/mca/hwloc/hwloc.h or whether to include the system-installed
hwloc.h).
This commit:
1. Renames opal/mca/hwloc/hwloc.h to hwloc-internal.h.
2. Adds opal/mca/hwloc/autogen.options to tell autogen.pl to expect to
find hwloc-internal.h (instead of hwloc.h) in opal/mca/hwloc.
3. s@opal/mca/hwloc/hwloc.h@opal/mca/hwloc/hwloc-internal.h@g in the
rest of the code base.
Signed-off-by: Jeff Squyres <jsquyres@cisco.com>