LONDON (Reuters) - A military option must remain on the table in dealing with North Korea s nuclear program, Foreign Secretary Boris Johnson said on Monday, adding that nobody wants tensions in the Korean peninsula to be resolved in such a way.      I don t think anybody could conceivably want a military solution to this problem,  Johnson said at a speech in London.  And yet clearly... the possibility of some kind of military option... that possibility must at least theoretically be maintained on the table.  