fix(contrib/ec2): fix ephemeral port range

The default ephemeral port range is set to 49152 according to
http://www.ncftp.com/ncftpd/doc/misc/ephemeral_ports.html. Some
apps that start on 49153 will be blocked by the firewall otherwise.
Merge pull request #827 from deis/fix-ephemeral-port-range

fix(contrib/ec2): fix ephemeral port range