[ntuple] Fix DAOS test compilation for old CMake
[ntuple] Fix DAOS test compilation for old CMake

When trying to build the tests (CMake 3.10), R__DAOS_TEST_POOL was not
getting defined correctly which caused build errors like:

expected ‘)’ before ‘R__DAOS_TEST_POOL’
    5 |    std::string daosUri("daos://" R__DAOS_TEST_POOL ":1/a947484e-e3bc-48cb-8f71-3292c19b59a4");
      |                       ~         ^~~~~~~~~~~~~~~~~~
      |                                 )

Moving from COMPILE_OPTIONS to COMPILE_DEFINITIONS seemed to fix it.

olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root