The battle for RJR Nabisco Holdings Corp. is over. Tuesday, on the eve of RJR's annual meeting, investor Bennett LeBow conceded defeat in his attempt to win control of the company. That ends any plans for rival tobacco companies to follow the lead of Mr. LeBow's Liggett Co. in voluntarily agreeing to restrictive ad rules proposed by the U. S. Food & Drug Administration. Had he taken over RJR, Mr. LeBow planned to spin off RJ Reynolds Tobacco Co. He had said that if Liggett merged with RJ Reynolds, Reynolds would be covered by the same type of ad restrictions as Liggett. But Mr. Bennett's attempt to settle some state actions against Liggett by agreeing to pay "damages" and accept FDA rules backfired. Instead of investors jumping over to his cause, hoping he had eliminated potential liability, most investors sided with RJR, apparently feeling the move wouldn't eliminate suits and could become more costly.