fix: optional / for /person/merge/ URL (#7746)

ietf/person/urls.py

@@ -2,7 +2,7 @@
 from ietf.utils.urls import url
 
 urlpatterns = [
-    url(r'^merge/$', views.merge),
+    url(r'^merge/?$', views.merge),
     url(r'^search/(?P<model_name>(person|email))/$', views.ajax_select2_search),
     url(r'^(?P<personid>[0-9]+)/email.json$', ajax.person_email_json),
     url(r'^(?P<email_or_name>[^/]+)$', views.profile),