Order EmbeddedServletContainerCustomizers

Add Ordered interface to all EmbeddedServletContainerCustomizers with
a value of 0. Prior to this commit it was difficult for a user to
define a customizer that would be applied before ours, even if they
implemented Ordered or added @Order annotations.

Fixes gh-2123

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/EndpointWebMvcChildContextConfiguration.java

@@ -50,6 +50,7 @@ import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomi
 import org.springframework.boot.context.embedded.ErrorPage;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.Ordered;
 import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
 import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
 import org.springframework.web.servlet.DispatcherServlet;
@@ -79,7 +80,7 @@ public class EndpointWebMvcChildContextConfiguration {
 
 	@Configuration
 	protected static class ServerCustomization implements
-			EmbeddedServletContainerCustomizer {
+			EmbeddedServletContainerCustomizer, Ordered {
 
 		@Value("${error.path:/error}")
 		private String errorPath = "/error";
@@ -93,6 +94,11 @@ public class EndpointWebMvcChildContextConfiguration {
 
 		private ServerProperties server;
 
+		@Override
+		public int getOrder() {
+			return 0;
+		}
+
 		@Override
 		public void customize(ConfigurableEmbeddedServletContainer container) {
 			if (this.managementServerProperties == null) {