No way to disable logging to ./logs-... file

[omron93]

The init_logging() adds logging to a file in current working directory.

But because the sros napalm driver is loaded "dynamically" from napalm library (get_network_driver() function), it's very hard to disable this logging to file and use different logging setup (e.g. to syslog, or even no logging).

Please add possibility to disable this logging file handler and not changing logging module setting.

[jbemmel]

See #71

There was no need to do custom log configuration, let's remove it

[omron93]

That's great, exactly what I needed. Thank you @jbemmel