OSHMEM: port 6 patches from git mirror to svn

Subject: [PATCH 1/6] OSHMEM: mkey refactoring
mkey can be either shared memory style id or it can be
arbitrary byte string
removed hack that used spml_context to store generic keys
coding style fixes

Subject: [PATCH 2/6] OSHMEM: added support of MXM 2.0 rc transport
coding style fixed, typos, check error condition

Subject: [PATCH 3/6] OSHMEM: mxm2.0: remove PTL_SELF
There is no need to have special case for 'self'
connection in mxm 2.0. It also solves the problem
of passing incorrect mkey when doing put/get to
self

Subject: [PATCH 4/6] OSHMEM: fixes mxm fadd
give a dummy buffer if doing atomic add

Subject: [PATCH 5/6] OSHMEM: mxm2.0: do not use MXM_REQ_FLAG_SEND_LAZY
Subject: [PATCH 6/6] OSHMEM: remove unused include, causes compilation fail on ubuntu

Refs #3763