Merge pull request #1184 from bobby/ec2_vpc-without-subnets

Fixes regression introduced by edf1ac1ea6

cloud/amazon/ec2_vpc.py

@@ -486,6 +486,7 @@ def create_vpc(module, vpc_conn):
             'id': sn.id,
         })
 
+    if subnets is not None:
         # Sort subnets by the order they were listed in the play
         order = {}
         for idx, val in enumerate(subnets):