Removed update to last_E since we dont need that in MG mode
Removed update to last_E since we dont need that in MG mode

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