Added a serial version uid.

examples/helloworld-servlet/src/main/java/org/ow2/frascati/examples/helloworld/servlet/HelloWorldHttpServlet.java

@@ -32,10 +32,11 @@ import javax.servlet.http.HttpServletResponse;
 
 import org.osoa.sca.annotations.Property;
 
-@SuppressWarnings("serial")
 public class HelloWorldHttpServlet
      extends HttpServlet
 {
+	private static final long serialVersionUID = 1L;
+
 	/**
 	 * A configurable property 'name'.
 	 */