Issue2253

To reproduce:
- Import _socket module directly or indirectly
- Register one or more logging handlers
- Remove all registered handlers

As a result you got the following message printed to stderr when the interpreter exits:

    No handlers could be found for logger "_socket"

An easy way to reproduce this is running the attached script. I have tested with official beta 3 and latest beta 4 soft launch version.

See also related #2254.

I looked at `logging` code and found out that we can avoid this warning by setting `log.manager.emittedNoHandlerWarning` to True. This is thus how both this and #2254 could be fixed:

    log = logging.getLogger("_socket")
    log.manager.emittedNoHandlerWarning = True
    log.propagate = False

Another solution to fix this would be always registering a handler to the acquired logger and then setting log level to WARNING. If debug logging is needed, level can be then set to DEBUG. This would probably be cleaner than setting somewhat private `manager.emittedNoHandlerWarning`.

Fixed as of https://hg.python.org/jython/rev/e37122c32d8a