RDMA/nes: Don't set 0-length FULPDU RTR indication control flag

Don't set control flag for 0-length FULPDU (Send) RTR indication
in the enhanced MPA Request/Reply frames, because it isn't supported.

Signed-off-by: Tatyana Nikolova <tatyana.e.nikolova@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>