The dawn call to prayer echoed through the Ramadan morning. Just before 5 a.m., a van pulled over on the side of the road. Within seconds, four passengers climbed in. They had been waiting in the spring night air of the Badiya, Syria’s desert. For 35,000 Syrian pounds (about $3), the driver took them toward the arid steppes west of the town of al-Shola, nearly 20 miles from Deir ez-Zor. On this March morning, hundreds were converging on the area…