Fix threshold index check for photoelectric cross sections
Fix threshold index check for photoelectric cross sections

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