Formula Cache is not purged at startup

In commit 83f8790, on 11/8/2009 Sergiu renamed the cache id from "xwiki.plugin.equation" to "xwiki.plugin.formula" but he probably forgot to rename it in the jboss cache configuration file. On 10/10/2011 (rev 04b63f5) Thomas introduced the config.xml file for infinispan, probably coying what was in the older jboss cache, which lead to having the following:

   <!-- Equation plugin cache -->
   <namedCache name="xwiki.plugin.equation">
      <loaders>
         <loader class="org.infinispan.loaders.file.FileCacheStore" purgeOnStartup="true">
           <!-- Let XWiki cache module set the proper location -->
         </loader>
      </loaders>
   </namedCache>