romio/daos: better conditionals to build with libdaos.so.0/1

[kccain]

Enhance the conditional compilation logic in the daos adio
driver for compiling against libdaos.so.0 (old API) that does not
provide a DAOS_API_MAJOR_VERSION preprocessor macro.

Signed-off-by: Kenneth Cain kenneth.c.cain@intel.com

Pull Request Description

Expected Impact

Author Checklist

• Reference appropriate issues (with "Fixes" or "See" as appropriate)
• Remove xfail from the test suite when fixing a test
• Commits are self-contained and do not do two things at once
• Commit message is of the form: module: short description and follows good practice
• Passes whitespace checkers
• Passes warning tests
• Passes all tests
• Add comments such that someone without knowledge of the code could understand
• You or your company has a signed contributor's agreement on file with Argonne
• For non-Argonne authors, request an explicit comment from your companies PR approval manager

[kccain]

It is TBD if this PR will be landed. Or if instead, the code changes may simply be included in PR 44.