start logging all modules (not just default) from fetch_logs

Test Plan:
- clone the analyitcs repo to /ebs/modeling/jace/analytics
- copy the two modified files
- in fetch_logs.sh, further modify `log_dir=/ebs/modeling/jace/kalogs`
- run fetch_logs.sh with no args
- verify that output looks sane, contains a few extra lines from
  highmem and backend modules.

Reviewers: chris

Differential Revision: http://phabricator.khanacademy.org/D8465