“ Subject to article 17, summary courts-martial shall have jurisdiction to try persons subject to this code except officers, warrant officers, cadets, aviation cadets, and midshipmen for any noncapital offense made punishable by this code. No person with respect to whom summary courts-martial have jurisdiction shall be brought to trial before a summary court-martial if he objects thereto, unless under the provisions of article 15 he has been permitted and has elected to refuse punishment under such article. ”