Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=56273
If the Manager web application does not perform an operation because the web application is already being serviced, report an error rather than reporting success.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1580514 13f79535-47bb-0310-9956-ffa450edef68