This patch brings in the removal of debug logging altogether, instead
we bring in the functionality of being able to trace the errors properly
pointing back to the origination of the problem.
To enable tracing you need to enable "MINIO_TRACE" set to "1" or "true"
environment variable which would print back traces whenever there is an
error which is unhandled or at the handler layer.
By default this tracing is turned off and only user level logging is
provided.
Since there is a good amount of overlap, each code has to lock
properly for the operation they are going to perform.
- MakeVol create vols in a routine on all disks, hold locks.
- DeleteVol delete vols in a routine on all disks, hold locks.
- StatVol stat vols in a routine on all disks, hold locks.
Fixes#1588
