OSHMEM: fix the makefile.

(oshmem/mca/sshmem/base/Makefile.am)

(cherry picked from commit 1eb6286547780e965b8b933bd67b0c42d6969714)

Conflicts:
	oshmem/mca/sshmem/base/Makefile.am

open-mpi/ompi@1eb6286547780e965b8b933bd67b0c42d6969714

@miked-mellanox @jladd-mlnx