Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=57261
Change /vminfo and /threaddump Manager commands to print an "OK -" line, thus aligning them with other commands. Document them.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1643731 13f79535-47bb-0310-9956-ffa450edef68