Fix lint

Author: esrakartalOpt

lib/optimizely/event/entity/event_batch.rb

@@ -48,7 +48,7 @@ def build
         event_batch.anonymize_ip = @anonymize_ip
         event_batch.enrich_decisions = @enrich_decisions
         event_batch.visitors = @visitors
-        event_batch.region = @region.nil? || 'US': @region
+        event_batch.region = @region || 'US'
         event_batch
       end