Hedge fund manager Dan Loeb participates in a panel discussion in Las Vegas, Nevada, U.S., May 9, 2012. REUTERS/Steve Marcus LONDON, June 15 (Reuters Breakingviews) - Vivendi’s (VIV.PA) doughty activists are fighting a losing war. Veteran corporate agitator Dan Loeb and others have plenty to criticise in the 35 billion euro French media conglomerate’s messy plan to list Universal Music. That is unlikely to prevent owner Vincent Bolloré and suitor Bill Ackman from getting their way. Loeb’s Third Point has amassed a substantial stake in Vivendi, adding a new twist to an already convoluted deal saga.