Use ingress operator config region for AWS session if available

AWS API connections in certain regions require that the session specify
the correct region, otherwise STS authentication can fail. This commit
addresses this by setting the region in the session explictly to match
the region set in the platform status

pkg/dns/aws/dns.go

@@ -113,6 +113,9 @@ func NewProvider(config Config, operatorReleaseVersion string) (*Provider, error
 	if config.CustomCABundle != "" {
 		sessionOpts.CustomCABundle = strings.NewReader(config.CustomCABundle)
 	}
+	if len(config.Region) > 0 {
+		sessionOpts.Config.Region = aws.String(config.Region)
+	}
 	sess, err := session.NewSessionWithOptions(sessionOpts)
 	if err != nil {
 		return nil, fmt.Errorf("couldn't create AWS client session: %v", err)