Make logging friendlier when not connecting to OpenSRF

OpenSRF 3.2.1

In some scenarios, it's useful for Perl clients to use OpenSRF (or Evergreen) code libraries that make use of the $logger without actually connecting to the OpenSRF network. Without the connection, the logger cannot initialize its configuration and defaults to logging to stderr, preceded by warnings about lack of config.

I propose a way for clients to set the loglevel and to specify logs should be delivered to STDOUT instead of STDERR when no configuration is available.

$logger->set_log_stdout(1);
$logger->set_log_level($logger->INFO);