Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=55439
Don't try a forced stop (kill -9 $PID) if Tomcat has already been stopped and the PID file cleared else a bunch of errors will result.
Additionally, improve handling in a forced stop of situation when the PID file can be written to  but not deleted.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1515926 13f79535-47bb-0310-9956-ffa450edef68