QPID-4735: ACL file size/count upper limit checks incorrect

Merge IntMin and IntMax functions into a single function to contain duplicated code.
Improve log messages so that reading a log file is less painful.
Turn on ACL debug logging for main broker in ACL self test.



git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1466652 13f79535-47bb-0310-9956-ffa450edef68