fix ring failure in 2014-07-31-14:16:58

Link: https://github.com/GeneAssembly/biosal/issues/488
Link: http://biosal.s3.amazonaws.com/quality-assurance-department/2014-07-31-14:16:58.log
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>