added other_old to _swap_filter method
added other_old to _swap_filter method

shikhar413/openmc,wbinventor/openmc,mit-crpg/openmc,paulromano/openmc,amandalund/openmc,walshjon/openmc,amandalund/openmc,paulromano/openmc,wbinventor/openmc,smharper/openmc,johnnyliu27/openmc,smharper/openmc,paulromano/openmc,smharper/openmc,shikhar413/openmc,amandalund/openmc,liangjg/openmc,walshjon/openmc,mit-crpg/openmc,liangjg/openmc,liangjg/openmc,mit-crpg/openmc,johnnyliu27/openmc,walshjon/openmc,wbinventor/openmc,johnnyliu27/openmc,amandalund/openmc,wbinventor/openmc,shikhar413/openmc,liangjg/openmc,mit-crpg/openmc,johnnyliu27/openmc,smharper/openmc,shikhar413/openmc,paulromano/openmc,walshjon/openmc