BZ 56703: Fix inflated counter for current number of
backend connections in status worker.

If an error occured during using a connection and the
connection was known to be already shut down by lower
level functions, the code to clean up did not decrement
the connection counter.

The most likely such situation was when a connection
timeout occured on the backend.


git-svn-id: https://svn.apache.org/repos/asf/tomcat/jk/trunk@1618000 13f79535-47bb-0310-9956-ffa450edef68