Make log level debug for "Ignoring limits"

Change-Id: I1d34b9cea39922d9fb928aeda88854c3f600fd88
diff --git a/src/main/java/com/googlesource/gerrit/plugins/quota/AccountLimitsFinder.java b/src/main/java/com/googlesource/gerrit/plugins/quota/AccountLimitsFinder.java
index 1961efb..43d3a19 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/quota/AccountLimitsFinder.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/quota/AccountLimitsFinder.java
@@ -53,7 +53,7 @@
       for (String groupName : limits.get().keySet()) {
         GroupDescription.Basic d = groupsCollection.parseId(groupName);
         if (d == null) {
-          log.error("Ignoring limits for unknown group ''{}'' in quota.config", groupName);
+          log.debug("Ignoring limits for unknown group ''{}'' in quota.config", groupName);
         } else if (memberShip.contains(d.getGroupUUID())) {
           return Optional.ofNullable(limits.get().get(groupName));
         }