Redirect shellcheck output to stderr in lint-scripts
Redirect shellcheck output to stderr in lint-scripts

On Travis, when shellcheck failed, nothing went in the log file because
stdout was not printed.  It was not easy to find out what went wrong.

This redirects any shellcheck stdout to stderr because shellcheck only
outputs errors anyway.

Connexions/cnx-rulesets,Connexions/cnx-rulesets,Connexions/cnx-recipes,Connexions/cte,Connexions/cnx-rulesets,Connexions/cnx-recipes,Connexions/cte,Connexions/cnx-recipes,Connexions/cnx-rulesets,Connexions/cnx-recipes,Connexions/cnx-recipes