Add MRC machines to "spiders" list.
Add MRC machines to "spiders" list.

These machines should be ignored when computing usage statistics.

ojacobson/dryad-repo,mdiggory/dryad-repo,rnathanday/dryad-repo,rnathanday/dryad-repo,jamie-dryad/dryad-repo,ojacobson/dryad-repo,jimallman/dryad-repo,mdiggory/dryad-repo,jamie-dryad/dryad-repo,mdiggory/dryad-repo,rnathanday/dryad-repo,jamie-dryad/dryad-repo,mdiggory/dryad-repo,rnathanday/dryad-repo,ojacobson/dryad-repo,jamie-dryad/dryad-repo,jamie-dryad/dryad-repo,jimallman/dryad-repo,mdiggory/dryad-repo,jimallman/dryad-repo,jimallman/dryad-repo,rnathanday/dryad-repo,jimallman/dryad-repo,ojacobson/dryad-repo,ojacobson/dryad-repo,ojacobson/dryad-repo,jimallman/dryad-repo,rnathanday/dryad-repo