set duplicate as a reject reason in email for theme queue

mkt/reviewers/tasks.py

@@ -25,6 +25,8 @@ def send_mail(cleaned_data, theme_lock):
     reason = None
     if reject_reason:
         reason = rvw.THEME_REJECT_REASONS[reject_reason]
+    elif action == rvw.ACTION_DUPLICATE:
+        reason = _('Duplicate Submission')
     comment = cleaned_data['comment']
 
     emails = set(theme.addon.authors.values_list('email', flat=True))
@@ -45,13 +47,11 @@ def send_mail(cleaned_data, theme_lock):
         subject = _('A problem with your Theme submission')
         template = 'reviewers/themes/emails/reject.html'
         theme.addon.update(status=amo.STATUS_REJECTED)
-        reason = (rvw.THEME_REJECT_REASONS[reject_reason])
 
     elif action == rvw.ACTION_DUPLICATE:
         subject = _('A problem with your Theme submission')
         template = 'reviewers/themes/emails/reject.html'
         theme.addon.update(status=amo.STATUS_REJECTED)
-        reason = 'Duplicate'
 
     elif action == rvw.ACTION_FLAG:
         subject = _('Theme submission flagged for review')

mkt/reviewers/tests/test_views.py

@@ -2136,12 +2136,12 @@ class ThemeReviewTestMixin(object):
                 recipient_list=[settings.THEMES_EMAIL]),
             mock.call('A problem with your Theme submission',
                 'reviewers/themes/emails/reject.html',
-                {'reason': None,
+                {'reason': mock.ANY,
                  'comment': u'duplicate',
                  'theme': themes[2],
                  'base_url': 'http://testserver'},
                 headers={'Reply-To': settings.THEMES_EMAIL},
-                 recipient_list=set([])),
+                recipient_list=set([])),
             mock.call('A problem with your Theme submission',
                 'reviewers/themes/emails/reject.html',
                 {'reason': mock.ANY,