Change "Add new dataset" to "Add Dataset"

Text on button on user's dashboard. Make it match "Add Dataset" link in
site header, "Add Dataset" and "Add Dataset to Group" buttons on group
pages, etc.

ckan/templates/user/dashboard.html

@@ -11,7 +11,7 @@
 
 {% block actions_content %}
   {% if h.check_access('package_create') %}
-    <li>{% link_for _('Add new dataset'), controller='package', action='new', class_="btn btn-primary icon-large", icon="plus" %}</li>
+    <li>{% link_for _('Add Dataset'), controller='package', action='new', class_="btn btn-primary icon-large", icon="plus" %}</li>
   {% endif %}
 {% endblock %}