By Timour Azhari and Phil Stewart BAGHDAD (Reuters) -The United States and Iraq are set to initiate talks on the end of a U.S.-led international military coalition in Iraq and how to replace it with bilateral relations, four sources said, a step forward in a process that was stalled by the Gaza war. The U.S. conveyed the message in a letter handed over by U.S. Ambassador to Iraq Alina Romanowski to Iraqi Foreign Minister Fuad Hussein on Wednesday, three sources said. In doing so, the U.S. had dropped preconditions that attacks against it by Iran-backed Iraqi militant groups in Iraq first stop,…