rdma: carry the session id in the reaped session record

The session id only existed as the sessions map key; the session
record itself kept an empty id string, so the terminal reap record
logged an empty id for every expired, cancelled, or destroyed
session. Copy the id into the record at creation time so teardown
logs identify the session they describe.

cuwrapper/rc/rc_server_abi.cpp

@@ -613,6 +613,10 @@ int rc_prepare(rc_server *srv, const rc_prepare_req *req,
       srv->opts.t_prep_ms
           ? hipObj::v2::clockSource().nowMs() + srv->opts.t_prep_ms
           : 0;
+  /* The session record carries its own id copy: reap logging and the
+   * terminal teardown record read core.id, while the map key is the
+   * only other place the id lives. */
+  rs.core.id = id;
   {
     std::lock_guard<std::mutex> g(srv->map_mtx);
     rs.staging_buf = reinterpret_cast<uint8_t *>(buf);