Correct doctype for generated web.xml files and add declaration to test file.

core/src/main/resources/acegi-web.xsl

@@ -14,7 +14,7 @@
 <xsl:param name="acegi-security-context-file" select="'applicationContext-acegi-security.xml'"/>
 
 <xsl:output doctype-public="-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
-        doctype-system="http://java.sun.com/J2EE/dtds/web-app_2_3.dtd"
+        doctype-system="http://java.sun.com/dtd/web-app_2_3.dtd"
         indent="yes"/>
 
 <!-- Identity template which we override for specific cases -->

core/src/test/resources/test-web.xml

@@ -1,3 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
+
 <web-app>
   <display-name>login-xml</display-name>