Support Swift log file archive for HAProxy driver.

Fixes bug #1156852.

This adds the support for archiving HAProxy log files to Swift.
Files will be organized into containers based on load balancer
ID. Object names will be 'haproxy-YYYMMDD-HHMMSS.log.gz' where
the timestamp portion is current UTC time when the file is stored.
Files are Gzip compressed.

Change-Id: I5e9007ca816f4834d477be42e1cfa1624d33b54e