Update PML for latest BTL update
Fix knem support in both sm and vader
First crack at adding atomic operation support
pml/ob1: bug fixes and adjustments for changes in btl_sendi behavior
btl: fix warning about enum type and modify btl_sendi to allow the
value NULL for the descriptor

The send inline optimization uses the btl_sendi function to achieve
lower latency and higher message rates. The problem is the btl_sendi
function was allowed to return a descriptor to the caller. This is fine
for some paths but not ok for the send inline optimization. To fix
this the btl now must be able to handle descriptor = NULL.
btl/sm fix compilation when not using CMA or KNEM
more openib updates
btl/openib: fix recieve queue source detection
btl/openib: fix message coalescing
btl/openib: misc cleanup (tabs, etc) and put credit code into a common place (was duplicated in the send and sendi paths)
btl/ugni: add support for atomic operations
Fix ob1 warnings
Rename the OSC "rdma" component to pt2p to better reflect that it does not actually use btl rdma
ugni thread safety fixes
ob1 warning fix
add more internal RMA error codes
osc/pt2pt: threading fixes and code cleanup
btl/openib: add atomic operation support
bml/r2: add all rdma btls even if another btl has higher exclusivity

Background: In order to support atomics each btl needs to provide support
for communicating with self unless the btl module can guarantee global
atomicity. Before this commit bml/r2 discarded any BTL with lower
exclusivity than an existing send btl. This would cause the BML to
discard any btl other than self.

The new behavior is as follows:

 - If an exisiting send btl has higher exclusivity then the btl will not be
   added to the send btl list for the endpoint.

 - If a btl provides RDMA support then it is always added to the rdma btl
   list.

 - bml_btl weight for send btls is now calculated across all send btls.

 - bml_btl weight for rdma btls is now calculated across all rdma btls.

With this change self should still win as the only send btl for loopback
without disqualifying other btls (ugni, openib) for atomic operations.