Fix rqworker workhorse log level.

Remove the RQ workhorse log level monkey patch since the new version of RQ has
solved my bug.

Also add an environment variable CLOUDLY_LOG_LEVEL for setting the log level of
the logger provided by cloudly.

Version: 1.1.0
Merge pull request #5 from ooda/fix-rq-logger

Fix rqworker workhorse log level.