Revert "Pull out edX into variables in password reset email"

This reverts commit 3a2276b5.

lms/templates/registration/password_reset_email.html

 {% load i18n %}{% load url from future %}{% autoescape off %}
-{% blocktrans with site_name=site_name %}You're receiving this e-mail because you requested a password reset for your user account at {{ site_name }}.{% endblocktrans %}
+{% blocktrans %}You're receiving this e-mail because you requested a password reset for your user account at edx.org.{% endblocktrans %}
 
 {% trans "Please go to the following page and choose a new password:" %}
 {% block reset_link %}
@@ -10,6 +10,6 @@ http{% if is_secure %}s{% endif %}://{{domain}}{% url 'student.views.password_re
 
 {% trans "Thanks for using our site!" %}
 
-{% blocktrans with platform_name=platform_name %}The {{ platform_name }} Team{% endblocktrans %}
+{% blocktrans %}The edX Team{% endblocktrans %}
 
 {% endautoescape %}