make property injection optional

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/ribbon/DefaultServerIntrospector.java

@@ -30,8 +30,12 @@ import java.util.Map;
  */
 public class DefaultServerIntrospector implements ServerIntrospector {
 
-	@Autowired
-	private ServerIntrospectorProperties serverIntrospectorProperties;
+	private ServerIntrospectorProperties serverIntrospectorProperties = new ServerIntrospectorProperties();
+
+	@Autowired(required = false)
+	public void setServerIntrospectorProperties(ServerIntrospectorProperties serverIntrospectorProperties){
+		this.serverIntrospectorProperties = serverIntrospectorProperties;
+	}
 
 	@Override
 	public boolean isSecure(Server server) {

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/ribbon/RibbonAutoConfiguration.java

@@ -61,7 +61,7 @@ import com.netflix.ribbon.Ribbon;
 @RibbonClients
 @AutoConfigureAfter(name = "org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration")
 @AutoConfigureBefore({LoadBalancerAutoConfiguration.class, AsyncLoadBalancerAutoConfiguration.class})
-@EnableConfigurationProperties(RibbonEagerLoadProperties.class)
+@EnableConfigurationProperties({RibbonEagerLoadProperties.class, ServerIntrospectorProperties.class})
 public class RibbonAutoConfiguration {
 
 	@Autowired(required = false)