Fixes #4215: Move r30532 to v1.7 branch (r30519 (and the associated CMR)

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r30532 [[BR]]
r30519 (and the associated CMR #4209) left out fixing
MPI_SUBARRAYS_SUPPORTED and MPI_ASYNC_PROTECTS_NONBLOCKING in the F08
descriptor prototype.

This commit fixes the F08 descriptor prototype in the same was as
r30519 did for the non-F08-descriptor implementation.

Thanks to Mike Dubman for finding the issue.

cmr=v1.7.4:reviewer=ompi-rm1.7
Apply a portion of r30534 that matches the current state of the v1.7.4 branch to resolve problems with misuse of "MB" instead of "opal_atomic_wmb". The changeset was done on the trunk by Nathan, and I've discussed it with Brian to ensure this is the right thing to do.

Refs #4158