ISLAMABAD, Nov 3 (Reuters) - The U.S. commander running the wars in Iraq and Afghanistan, General David Petraeus, held talks on Monday with Pakistani defence officials who told him Pakistan was fighting a war for its survival against militancy. His visit to Pakistan, apparently his first stop on a foreign tour since taking charge of U.S. Central Command on Friday, highlights U.S. concern about a country seen as crucial to stability in Afghanistan and to defeating al Qaeda. U.S. analysts say Pakistan is facing a major threat from Islamist militants at a time when the nuclear-armed nation and its new...