Add missing import

Author: LEDfan

src/main/java/eu/openanalytics/containerproxy/auth/impl/OpenIDAuthenticationBackend.java

@@ -69,6 +69,7 @@
 import net.minidev.json.JSONArray;
 import net.minidev.json.parser.JSONParser;
 import net.minidev.json.parser.ParseException;
+import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
 
 public class OpenIDAuthenticationBackend implements IAuthenticationBackend {