Fixes #4281: Improve access to buffers.

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r30745 [[BR]]
Improve access to buffers.

r30775 [[BR]]
Comments about 'db' arguments.
Fixes #4289: Move r30779 to v1.7 branch (OSHMEM: OOM in yoda)

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r30779 [[BR]]
OSHMEM: OOM in yoda

fix: do not fail on blm allocation error, wait for some puts to complete and retry

fixed by Roman, reviewed by Mike/Alex
cmr=v1.7.5:reviewer=ompi-rm1.7