Use HVM instance for EBS creator, guarantees everything is created in…

… the correct zone.

(cherry picked from commit c9763e2)

nixos/maintainers/scripts/ec2/ebs-creator.nix

@@ -4,7 +4,7 @@
   machine =
     { config, pkgs, resources, ... }:
     { deployment.targetEnv = "ec2";
-      deployment.ec2.instanceType = "m1.large";
+      deployment.ec2.instanceType = "c3.large";
       deployment.ec2.securityGroups = [ "admin" ];
       deployment.ec2.ebsBoot = false;
       deployment.ec2.keyPair = resources.ec2KeyPairs.keypair.name;