fix for SITE_NAME in body of email; is was not being displayed (closes:...

fix for SITE_NAME in body of email; is was not being displayed (closes: mentors.debian.net-team/debexpo#132)

debexpo/packages/templates/email-upload-removed.html

 {% extends "email-base.html" %}{% block content %}Hi,
 
 Your package {{ args.package }} has been removed from {{ args.distribution }}
-on {{ args.settings.SITE_NAME }} for the following reason:
+on {{ settings.SITE_NAME }} for the following reason:
 
 {{ args.reason }}