Rationalise the spacing on the job page

Having two different margin sizes here meant that the page jumped
slightly once the report was ready to download. No good reason in favour
of it.

app/templates/partials/jobs/notifications.html

@@ -24,7 +24,7 @@
 
       {% if not help %}
         {% if percentage_complete < 100 %}
-          <p class="bottom-gutter-1-2 hint">
+          <p class="bottom-gutter hint">
             Report is {{ "{:.0f}%".format(percentage_complete) }} complete…
           </p>
         {% elif notifications %}