RFR: 8077846: improve locking strategy for readConfiguration(), reset(), and initializeGlobalHandlers()

[Daniel Fuchs]

Hi,

Please find below a patch that tries to improve the locking
strategy in LogManager.

The patch proposes to use a Reantrant lock to deal with
configurations changes in reset() and readConfiguration(),
and avoids lock contention in  initializeGlobalHandlers()

http://cr.openjdk.java.net/~dfuchs/webrev_8077846/webrev.00/

comments welcome,

best regards,

-- daniel