By Parisa Hafezi and Angus McDowallDUBAI, March 10 (Reuters) - Iran's Revolutionary Guards forced through the choice of Mojtaba Khamenei as the new supreme leader, seeing him as a more pliant version of his father who would back their hardline policies, bludgeoning aside the concerns of pragmatists, senior Iranian sources said. Already very powerful, the Guards have gained yet greater sway since the war began and quickly overcame the misgivings of senior political and clerical figures whose oppo...