Use cross-platform commands from os in update_results.py.
Use cross-platform commands from os in update_results.py.

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