Correct typo in assigning ID to UFS mesh.
Correct typo in assigning ID to UFS mesh.

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