Improve relaxed enum binding

Update RelaxedConversionService to support more relaxed enum binding.

Fixes gh-1950

spring-boot-samples/spring-boot-sample-tomcat/src/main/java/sample/tomcat/web/SampleControllerAdvice.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sample.tomcat.web;
+
+import javax.servlet.DispatcherType;
+import javax.servlet.http.HttpServletRequest;
+
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ModelAttribute;
+
+@ControllerAdvice
+public class SampleControllerAdvice {
+
+	@ModelAttribute
+	public boolean test(HttpServletRequest request) {
+		if (DispatcherType.ERROR.equals(request.getDispatcherType())) {
+			return false;
+		}
+		System.out.println(request.getPathInfo());
+		throw new RuntimeException("test");
+	}
+
+}