Fix formatting.

Author: Kami

libcloud/compute/drivers/ec2.py

@@ -1650,9 +1650,7 @@ def create_node(
                 params["SecurityGroup.%d" % (sig + 1,)] = security_groups[sig]
 
         if ex_security_group_ids and not ex_subnet:
-            raise ValueError(
-                "You can only supply ex_security_group_ids" " combined with ex_subnet"
-            )
+            raise ValueError("You can only supply ex_security_group_ids" " combined with ex_subnet")
 
         security_group_ids = ex_security_group_ids
         security_group_id_params = {}