Increase log worker retry timeout length.

* modules/openstack_project/files/logstash/log-gearman-worker.py:
Increase the log worker retry timeout length to 255 seconds and do an
exponential backoff instead of retrying every second when incomplete
files are received. This should reduce load on the file server and make
console.html indexing more reliable.

Change-Id: I42d8f99b3ba2495bb1cac94c4b44e3598f7b9cb6
Merge "Increase log worker retry timeout length."