make instance startup checks more robust
make instance startup checks more robust

In some cases, EC2 API calls will fail if you attempt to query an
instance shortly after it has been created.  We originally worked
around this by always waiting 10 seconds before trying to query the
instance.  It seems this isn't quite long enough.

This patch works around that issue and also tries very hard to avoid
leaving a running instance behind and warns explicitly if that may
have happened.

jmcabandara/imagefactory,jmcabandara/imagefactory,LalatenduMohanty/imagefactory,redhat-imaging/imagefactory,henrysher/imagefactory,redhat-imaging/imagefactory,LalatenduMohanty/imagefactory,henrysher/imagefactory