Workaround for gophercloud.ServerById crashing, fixes #1257

gophercloud.ServerById is broken in v0.1.0 - it will crash if you feed it a
non-existing server ID (see [rackspace/gophercloud #168](https://github.com/rackspace/gophercloud/issues/168))

Instead, list all servers and iterate over them. If the server id isn't found,
return "DELETED" as a state. Not perfect but it works until next version of
gophercloud is released.
Fix typo
Sort AMI names in Artifact.String - fixes random test failures

With go tip, the output from Artifact.String will sometimes be output in a
different order than the tests. Sort the AMI strings before outputting.
See https://travis-ci.org/mitchellh/packer/jobs/28748467 for an example of this
failure.
Merge pull request #1305 from lflux/sort-ami-strings

Sort AMI names in Artifact.String - fixes random test failures
Update CHANGELOG.md

builder/amazon-common: Sort AMI strings before outputting [GH-1305]
Merge pull request #1304 from lflux/fix-openstack-serverid-crash

Fix openstack ServerById crash
Update CHANGELOG.md

builder/openstack: Workaround for gophercloud.ServerById crashing [GH-1257]