Suppress stdout from env loading script to avoid python exec pollution (#54)

Without this suppression environment loading scripts that give verbose
information (e.g. intel setvars.sh) will have these lines executed by
the Python `exec()` function. Best case, it is total nonsense and throws
an error, worst case it executes some catastrophic code.

Note that the loader still executes perceived differences in the env, so
users should be cautious about loading scripts and be aware of code
injection.

Author: islas

sane/env_from_script.sh

@@ -45,7 +45,9 @@ import json
 json.dump( env, open( "$save_env", "w" ), indent=2 )
 EOF
 
-. $script
+# Ensure that any rogue stdout from script does not pollute ingestion of
+# generated python commands. Perhaps later we can wrap and output this as stdout/log
+. $script &> /dev/null
 
 output=$( env )
 python3 << EOF