Email wording changes based on Sarina's review

lms/templates/emails/confirm_email_change.txt

@@ -1,8 +1,7 @@
 <%! from django.core.urlresolvers import reverse %>
 This is to confirm that you changed the e-mail associated with edX
 from ${old_email} to ${new_email}. If you did not make this request,
-please contact the course staff immediately. Contact information is
-listed at:
+please contact us immediately. Contact information is listed at:
 
 % if is_secure:
   https://${ site }${reverse('contact')}

lms/templates/registration/password_reset_email.html

@@ -5,7 +5,8 @@
 {% block reset_link %}
 https://{{domain}}{% url 'django.contrib.auth.views.password_reset_confirm' uidb36=uid token=token %}
 {% endblock %}
-{% trans "Your username, in case you've forgotten:" %} {{ user.username }}
+
+If you didn't request this change, you can disregard this email - we have not yet reset your password.
 
 {% trans "Thanks for using our site!" %}