Added try/finally in test_tally_nuclides.py.
Added try/finally in test_tally_nuclides.py.

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