Fix Python 3 support in statepoint.py
Fix Python 3 support in statepoint.py

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