OSHMEM: fix compilation error with pathscale

Thanks to  Ake Sandgren for patch

reviewed by Roman/Miked

cmr=v1.8.1:reviewer=ompi-rm1.8
OSHMEM: align with OSHMEM SPEC v1.0

- add some missing APIs
- change signature od shmem_finalize to comply with SGI spec

fixed by Roman, reviewed by Igor/Miked

Refs #4520