The Malian army prevented United Nations forces from patrolling the central town of Djenne, a hotbed of violence and jihadist activity in the Sahel, a UN spokesman said on Thursday, the latest in a string of snags for its mission there. The incident comes just weeks before a UN debate on whether to renew the mandate of the its mission in Mali with increased restrictions imposed on it by the ruling junta expected to factor into the decision. A Malian military official in the region said the patrol was only postponed, blaming the delay on military activities and on the mission, Minusma, itself. …