Fix logic error that meant that unpackWARs was ignored if a WAR failed to deploy (since the Context is an instance of FailedContext in that case)

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1545284 13f79535-47bb-0310-9956-ffa450edef68
Prevent a web application from deploying if it contains a context.xml, deployXML is false and there is no explicit descriptor as the descriptor may contain necessary security information.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1545288 13f79535-47bb-0310-9956-ffa450edef68