Have update_results.py run OpenMC twice when generating results for test_source_file. Closes #288 on github.
Have update_results.py run OpenMC twice when generating results for
test_source_file. Closes #288 on github.

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