bump benchmarkbbs
bump benchmarkbbs

Submodule src/code.cloudfoundry.org/benchmarkbbs 6aaf287..2f124f0:
  > fix arguments for placement tags

Signed-off-by: Brandon Shroyer <d370be3f39cb88690ed16d1a7b77debc20949e86@pivotal.io>

cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release