Update hwloc submodule to fix "make distcheck"

Hwloc upstream has fixed a problem with embedded "make distcheck" that
was breaking that surfaced when you ran autogen in an Open MPI
tarball.

This submodule update takes in the upstream hwloc fixes for this
issue.

Signed-off-by: Jeff Squyres <jsquyres@cisco.com>

Author: jsquyres