Logger targets were not race protected against concurrent updates from for example `HTTPConsoleLoggerSys`.
Restrict direct access to targets and make slices immutable so a returned slice can be processed safely without locks.
auditLog should be attempted right before the
return of the function and not multiple times
per function, this ensures that we only trigger
it once per function call.
This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`
