Allow /mappings to be disabled (fixes gh-1185)

Author: Dave Syer

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/RequestMappingEndpoint.java

@@ -24,6 +24,7 @@
 import java.util.Map;
 
 import org.springframework.beans.BeansException;
+import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.web.method.HandlerMethod;
@@ -35,6 +36,7 @@
  * 
  * @author Dave Syer
  */
+@ConfigurationProperties(prefix = "endpoints.mappings", ignoreUnknownFields = false)
 public class RequestMappingEndpoint extends AbstractEndpoint<Map<String, Object>>
 		implements ApplicationContextAware {