Make provisioning script stop immediately on errors

By default, bash will ignore any failing commands and happily proceed to
execute the next ones. This is usually not the behavior the we want in
provisioning script (or ever in scripts, actually): if one step of the
provisioning fails, it doesn't make much sense to proceed with the
following ones.

This simple patch uses `set -e` to ask bash to abort the whole script if
any command within it fails, leading to outputs that are easier to parse
since the commands following a failing one will usually fail also,
hiding the root cause.

provisioning/bootstrap.sh

@@ -1,5 +1,8 @@
 #!/bin/sh
 
+# Stop if an error is encountered
+set -e
+
 # Configuration de la base de données. Le mot de passe est constant car c'est
 # pour une installation de dév locale qui ne sera accessible que depuis la
 # machine virtuelle.

provisioning/prepare_django.sh

@@ -1,5 +1,8 @@
 #!/bin/bash
 
+# Stop if an error is encountered.
+set -e
+
 python manage.py migrate
 python manage.py loaddata gestion sites articles
 python manage.py loaddevdata