Fixed bug in openmc.mgxs for appending data to HDF5 files
Fixed bug in openmc.mgxs for appending data to HDF5 files

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