Natural order of AMI artifacts

builder/amazon/common/artifact.go

@@ -51,7 +51,7 @@ func (a *Artifact) String() string {
 	}
 
 	sort.Strings(amiStrings)
-	return fmt.Sprintf("AMIs were created:\n\n%s", strings.Join(amiStrings, "\n"))
+	return fmt.Sprintf("AMIs were created:\n%s\n", strings.Join(amiStrings, "\n"))
 }
 
 func (a *Artifact) State(name string) interface{} {

builder/amazon/common/artifact_test.go

@@ -48,9 +48,9 @@ func TestArtifactState_atlasMetadata(t *testing.T) {
 
 func TestArtifactString(t *testing.T) {
 	expected := `AMIs were created:
-
 east: foo
-west: bar`
+west: bar
+`
 
 	amis := make(map[string]string)
 	amis["east"] = "foo"