[MRM-1857] RSS feeds not working

Make sure Struts ignores the paths mapped to other servlets, including feeds
and xmlrpc. Also fix a context path issue for the feed on the repositories
page.

archiva-modules/archiva-web/archiva-webapp/src/main/resources/struts.xml

@@ -22,7 +22,7 @@
     "http://struts.apache.org/dtds/struts-2.0.dtd"> 
 
 <struts>
-  <constant name="struts.action.excludePattern" value="^/$,^/repository/.*" />
+  <constant name="struts.action.excludePattern" value="^/$,^/repository/.*,^/xmlrpc$,^/feeds/.*" />
 
   <!-- Include plexus-security xwork configurations. -->
   <include file="struts-security.xml"/>

archiva-modules/archiva-web/archiva-webapp/src/main/webapp/WEB-INF/jsp/admin/repositories.jsp

@@ -118,7 +118,8 @@
     </s:a>
   </redback:ifAnyAuthorized>
   <c:url var="rssFeedIconUrl" value="/images/icons/rss-feed.png"/>
-  <a href='/archiva/feeds/<c:out value="${repository.id}" />'>
+  <c:url var="rssFeedUrl" value="/feeds/${repository.id}" />
+  <a href="${rssFeedUrl}">
 	<img src="${rssFeedIconUrl}" />
   </a>
 </div>