quotas: correct multi org system limit

Refs GH-5227

Author: dcramer

src/sentry/quotas/base.py

@@ -115,14 +115,11 @@ def get_organization_quota(self, organization):
 
         # If there is only a single org, this one org should
         # be allowed to consume the entire quota.
-        if settings.SENTRY_SINGLE_ORGANIZATION:
-            if system_limit < account_limit:
+        if settings.SENTRY_SINGLE_ORGANIZATION or account_limit:
+            if system_limit and system_limit < account_limit:
                 return (system_limit, 60)
-            return (account_limit, 3600)
-
-        # an account limit is enforced, which is set as a fixed value and cannot
-        # utilize percentage based limits
-        elif account_limit:
+            # an account limit is enforced, which is set as a fixed value and cannot
+            # utilize percentage based limits
             return (account_limit, 3600)
 
         return (