Access realm by string_id in management commands.

`Realm.string_id` replaces 'Realm.domain'
in the management commands.

Fixes #2325.

analytics/management/commands/realm_stats.py

@@ -11,7 +11,7 @@ import pytz
 from django.core.management.base import BaseCommand
 from django.db.models import Count
 from zerver.models import UserProfile, Realm, Stream, Message, Recipient, UserActivity, \
-    Subscription, UserMessage, get_realm
+    Subscription, UserMessage, get_realm_by_string_id
 
 MOBILE_CLIENT_LIST = ["Android", "ios"]
 HUMAN_CLIENT_LIST = MOBILE_CLIENT_LIST + ["website"]
@@ -86,7 +86,7 @@ class Command(BaseCommand):
         # type: (*Any, **Any) -> None
         if options['realms']:
             try:
-                realms = [get_realm(domain) for domain in options['realms']]
+                realms = [get_realm_by_string_id(string_id) for string_id in options['realms']]
             except Realm.DoesNotExist as e:
                 print(e)
                 exit(1)
@@ -94,7 +94,7 @@ class Command(BaseCommand):
             realms = Realm.objects.all()
 
         for realm in realms:
-            print(realm.domain)
+            print(realm.string_id)
 
             user_profiles = UserProfile.objects.filter(realm=realm, is_active=True)
             active_users = self.active_users(realm)