tests: run-tests.sh shebang fix
tests: run-tests.sh shebang fix

* Adds the shebang to run-tests.sh.

Signed-off-by: Javier Delgado <5e5ca04284d36f70c75026b19c877319dd719efc@cern.ch>

inveniosoftware/invenio-mail,inveniosoftware/invenio-mail,inveniosoftware/invenio-mail