gnu: openmpi, slurm: Switch to hwloc 2.x.

* gnu/packages/mpi.scm (openmpi)[inputs]: Switch to HWLOC-2.
* gnu/packages/parallel.scm (slurm)[inputs]: Likewise.

gnu/packages/mpi.scm

@@ -177,7 +177,7 @@ (define-public openmpi
        (base32 "0ms0zvyxyy3pnx9qwib6zaljyp2b3ixny64xvq3czv3jpr8zf2wh"))))
     (build-system gnu-build-system)
     (inputs
-     `(("hwloc" ,hwloc "lib")
+     `(("hwloc" ,hwloc-2 "lib")
        ("gfortran" ,gfortran)
        ("libfabric" ,libfabric)
        ("libevent" ,libevent)

gnu/packages/parallel.scm

@@ -139,7 +139,7 @@ (define-public slurm
    ;; in particular mysql and gtk+.
    (inputs `(("expect" ,expect)
              ("freeipmi" ,freeipmi)
-             ("hwloc" ,hwloc "lib")
+             ("hwloc" ,hwloc-2 "lib")
              ("json-c" ,json-c)
              ("linux-pam" , linux-pam)
              ("munge" ,munge)