Description of problem:

Extra diagnostic connection needed for cases when qpidd hits max-connections count.

Bug 812244 scenario shows situation when user cannot analyze the broker's data.

It is necessary IMHO to enable the way to analyze data stored in the broker.

The proposal is following:
- introduce extra switch or a way (similar to runtime dynamic log level)
  which would switch between strict N connections (as it is now)
                         and N+1 connection mode
- The extra connection (in N+1 connection mode) can be used only by
  - python client
  - and only when all connections are used (connection cont == N)
  - and when connection cproc is 'qpid-(config|stat|cluster|tool)'
  - and optionally one more Connection property (if needed)


The proposal has to be reviewed as may introduces complexity.

Version-Release number of selected component (if applicable):
any

How reproducible:
100%

Steps to Reproduce:
1. see bug 812244 scenario
  
Actual results:
Connection limit strict.

Expected results:
Connection limit in two modes strict / less strict.

Additional info: