add diagnostics and recovery for possible connection leak.
add diagnostics and recovery for possible connection leak.

If request handlers didn't finalize the pooled connection, log the
request information and clean up for them.  We need to see if we're
experiencing leaks in the field that are not triggered by the test
suite...

informatics-isi-edu/ermrest,informatics-isi-edu/ermrest,ini-bdds/ermrest,ini-bdds/ermrest