Edit user encoding error

Hi
I get the following error in user/edit when the site_title contains a special character like é or à and with show_email_notifications enabled
```
Module /usr/lib/ckan/default/src/ckan/ckan/templates/user/edit_user_form.html:19 in template
<<      {% if c.show_email_notifications %}
             {% call form.checkbox('activity_streams_email_notifications', label=_('Subscribe to notification emails'), id='field-activity-streams-email-notifications', value=True, checked=c.userobj.activity_streams_email_notifications) %}
             {{ form.info(_("You will receive notification emails from {site_title}, e.g. when you have new activities on your dashboard.".format(site_title=g.site_title)), classes=['info-help-tight']) }}
             {% endcall %}
           {% endif %}
>>  {{ form.info(_("You will receive notification emails from {site_title}, e.g. when you have new activities on your dashboard.".format(site_title=g.site_title)), classes=['info-help-tight']) }}
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe9' in position 4: ordinal not in range(128)
```