CLN: Cleanup comments in before_install_travis.sh

envars.sh doesn't exist anymore.  In fact, it's been gone for awhile.

Author: gfyoung

ci/before_install_travis.sh

@@ -1,15 +1,10 @@
 #!/bin/bash
 
-# If envars.sh determined we're running  in an authorized fork
-# and the user opted in to the network cache,and that cached versions
-# are available on the cache server, download and deploy the cached
-# files to the local filesystem
-
 echo "inside $0"
 
-# overview
 if [ "${TRAVIS_OS_NAME}" == "linux" ]; then
    sh -e /etc/init.d/xvfb start
 fi
 
-true # never fail because bad things happened here
+# Never fail because bad things happened here.
+true