prov/verbs: Support fi_query_atomic

[arn314]

No description provided.

[bturrubiates]

This seems to cause a compiler warning on our Jenkins testing:

In file included from ./include/fi.h:52:0,
                 from prov/verbs/src/fi_verbs.h:64,
                 from prov/verbs/src/verbs_atomic.c:35:
prov/verbs/src/verbs_atomic.c: In function 'fi_ibv_query_atomic':
./include/rdma/providers/fi_log.h:77:10: error: 'log_str' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    fi_log(prov, level, subsystem,   \
          ^
prov/verbs/src/verbs_atomic.c:69:8: note: 'log_str' was declared here
  char *log_str;
        ^
cc1: all warnings being treated as errors
make[1]: *** [prov/verbs/src/src_libfabric_la-verbs_atomic.lo] Error 1