Remove check for Python 2.7 in travis-install
Remove check for Python 2.7 in travis-install

wbinventor/openmc,wbinventor/openmc,johnnyliu27/openmc,paulromano/openmc,smharper/openmc,shikhar413/openmc,liangjg/openmc,mit-crpg/openmc,mit-crpg/openmc,walshjon/openmc,amandalund/openmc,smharper/openmc,amandalund/openmc,shikhar413/openmc,johnnyliu27/openmc,liangjg/openmc,shikhar413/openmc,paulromano/openmc,mit-crpg/openmc,shikhar413/openmc,johnnyliu27/openmc,wbinventor/openmc,paulromano/openmc,amandalund/openmc,walshjon/openmc,walshjon/openmc,walshjon/openmc,liangjg/openmc,amandalund/openmc,mit-crpg/openmc,johnnyliu27/openmc,smharper/openmc,liangjg/openmc,wbinventor/openmc,paulromano/openmc,smharper/openmc