JcloudsLocation: allow disabling of opening IP Tables

Cherry-picked from https://github.com/brooklyncentral/brooklyn/pull/716, into 0.5 branch.

- Useful for some private subnet examples, where the hostname/url gets transformed.
- Transforms tests from groovy to Java.

- If not WAIT_FOR_SSHABLE then don't try to
  mapSecurityGroupRuleToIpTables.
  With private subnets, this fails because the IP that
  jclouds knows about isn't visible.
  Subsequent code in brooklyn can set up port-forwarding
  to make it usable, but this code blocked waiting and then
  failed.