Remove WARN log in Tomcat startup

spring-boot-samples/spring-boot-sample-web-static/src/main/resources/logback.xml

@@ -1,7 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<configuration>
-
-	<include resource="org/springframework/boot/logging/logback/base.xml"/>	
-	<logger name="org.springframework" level="DEBUG"/>
-	
-</configuration>

spring-boot/src/main/resources/org/springframework/boot/logging/logback/base.xml

@@ -36,5 +36,6 @@
 	<logger name="org.hibernate.validator.internal.util.Version" level="WARN"/>
 	<logger name="org.apache.coyote.http11.Http11NioProtocol" level="WARN"/>
 	<logger name="org.apache.tomcat.util.net.NioSelectorPool" level="WARN"/>
+	<logger name="org.apache.catalina.startup.DigesterFactory" level="ERROR"/>
 
 </included>