Adding retry logic to Loggly appenders

[ellisdc]

I have experienced periodic socket timeouts on the client side as well as server side 504 errors while using the loggly appenders, both of which seem to be temporary conditions. I added retry logic to both appenders that will retry failed requests up to the specified number of times. The default retry limit is 3 retries, but the user can specify the max retry limit in the appender configurations.

For the batch appender, I do not increment the failure count unless the retry limit has been reached.

The retry logic has thus far eliminated the periodic failures I was experiences (e.g. the request has always been successful on subsequent tries).