digest: Remove obsolete deployment code.

This system was quite complicated, and never had great semantics.

Eventually, we'll want some other system for gating which server
should generate digest emails for which realm controlled via the
database.

zerver/management/commands/enqueue_digest_emails.py

@@ -57,31 +57,11 @@ def queue_digest_recipient(user_profile, cutoff):
              "cutoff": cutoff.strftime('%s')}
     queue_json_publish("digest_emails", event, lambda event: None)
 
-def realms_for_this_deployment():
-    # type: () -> List[str]
-    if settings.ZILENCER_ENABLED:
-        # Voyager deployments don't have a Deployment entry.
-        # Only send zulip.com digests on staging.
-        from zilencer.models import Deployment
-        site_url = settings.EXTERNAL_URI_SCHEME + settings.EXTERNAL_HOST.rstrip("/")
-        try:
-            deployment = Deployment.objects.select_related('realms').get(
-                base_site_url__startswith=site_url)
-        except Deployment.DoesNotExist:
-            raise ValueError("digest: Unable to determine deployment.")
-
-        return [r.string_id for r in deployment.realms.all()]
-    # Voyager and development.
-    return []
-
-def should_process_digest(realm_str, deployment_realms):
-    # type: (str, List[str]) -> bool
+def should_process_digest(realm_str):
+    # type: (str) -> bool
     if realm_str in settings.SYSTEM_ONLY_REALMS:
         # Don't try to send emails to system-only realms
         return False
-    if settings.PRODUCTION and not settings.VOYAGER:
-        # zulip.com or staging.zulip.com
-        return realm_str in deployment_realms
     return True
 
 class Command(BaseCommand):
@@ -97,9 +77,8 @@ in a while.
         if timezone.now().weekday() not in VALID_DIGEST_DAYS:
             return
 
-        deployment_realms = realms_for_this_deployment()
         for realm in Realm.objects.filter(deactivated=False, show_digest_email=True):
-            if not should_process_digest(realm.string_id, deployment_realms):
+            if not should_process_digest(realm.string_id):
                 continue
 
             user_profiles = UserProfile.objects.filter(