JcloudsLocation: allow disabling of opening IP Tables

- 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.
Merge pull request #716 from aledsage/fix/JcloudsLocation-firewall

JcloudsLocation: allow disabling of opening IP Tables