Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=56321
When a WAR is modified, undeploy the web application before deleting any expanded directory as the undeploy process may refer to classes that need to be loaded from the expanded directory. If the expanded directory is deleted first, any attempt to load a new class during undeploy will fail.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1582454 13f79535-47bb-0310-9956-ffa450edef68