netrender balancing fix (accessing the list as it is being sorted is not ok)

Caused balancing to error when there was only one job (and more generally, to have a slightly wrong result)

release/scripts/io/netrender/balancing.py

@@ -72,7 +72,8 @@ class Balancer:
 	
 	def balance(self, jobs):
 		if jobs:
-			jobs.sort(key=self.sortKey)
+			# use inline copy to make sure the list is still accessible while sorting
+			jobs[:] = sorted(jobs, key=self.sortKey)
 			return jobs[0]
 		else:
 			return None