fix reading 2D string vector from attribute in hdf5
fix reading 2D string vector from attribute in hdf5

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