DAMASCUS - A six-car convoy of United Nations inspectors left a Damascus hotel on Monday and headed to the scene of a poison gas attack outside the Syrian capital last week, a Reuters witness said.The team of chemical weapons experts, dressed in blue UN body armor, were accompanied by security forces and an ambulance. They said they were headed to the rebel-held outskirts of Damascus, known as Eastern Ghouta, where activists say rockets loaded with poison gas killed hundreds of people.