Remove unneeded plot from periodic BC test
Remove unneeded plot from periodic BC test

paulromano/openmc,walshjon/openmc,mit-crpg/openmc,walshjon/openmc,mit-crpg/openmc,shikhar413/openmc,mit-crpg/openmc,shikhar413/openmc,amandalund/openmc,walshjon/openmc,paulromano/openmc,shikhar413/openmc,mit-crpg/openmc,paulromano/openmc,paulromano/openmc,amandalund/openmc,walshjon/openmc,amandalund/openmc,amandalund/openmc,shikhar413/openmc