BLK-128 BLK-215 When requests.get fails in RestPolling, go through the regular retry cycle rather than silently failing

Signed-off-by: Oren Leiman <oleiman@neutral.io>
Merge pull request #19 from nio-blocks/feature/get_fail_retry

BLK-128 BLK-215 When requests.get fails in RestPolling, go through the r...