[ec2] ensure mock describes don't return deleted stuff

lib/fog/aws/requests/ec2/describe_instances.rb

@@ -90,6 +90,7 @@ module Fog
               if Time.now - @data[:deleted_at][instance['instanceId']] > 1
                 @data[:deleted_at].delete(instance['instanceId'])
                 @data[:instances].delete(instance['instanceId'])
+                instance_set.delete(instance)
               end
             end
           end

lib/fog/aws/requests/ec2/describe_volumes.rb

@@ -61,6 +61,7 @@ module Fog
               if Time.now - @data[:deleted_at][volume['volumeId']] > 1
                 @data[:deleted_at].delete(volume['volumeId'])
                 @data[:volumes].delete(volume['volumeId'])
+                volume_set.delete(volume)
               end
             end
           end