Fix clean_xml.py indentation
Fix clean_xml.py indentation

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