Remove all vestiges of memcache

Memcache is already off but now it's not in the code anymore.

This includes removing domain creation failfast, since that is actually
slower now than just running the flow - all you gain is a non-transactional
read over a transactional read, but the cost is that you always pay that
read, which is going to drive up latency.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=158183506

java/google/registry/model/ofy/ObjectifyService.java

@@ -14,7 +14,6 @@
 
 package google.registry.model.ofy;
 
-import static com.google.appengine.api.memcache.ErrorHandlers.getConsistentLogAndContinue;
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.common.base.Predicates.not;
 import static com.googlecode.objectify.ObjectifyService.factory;
@@ -46,7 +45,6 @@ import google.registry.model.translators.InetAddressTranslatorFactory;
 import google.registry.model.translators.ReadableInstantUtcTranslatorFactory;
 import google.registry.model.translators.UpdateAutoTimestampTranslatorFactory;
 import java.util.concurrent.atomic.AtomicLong;
-import java.util.logging.Level;
 
 /**
  * An instance of Ofy, obtained via {@code #ofy()}, should be used to access all persistable
@@ -114,9 +112,6 @@ public class ObjectifyService {
     // Translators must be registered before any entities can be registered.
     registerTranslators();
     registerEntityClasses(EntityClasses.ALL_CLASSES);
-
-    // Set the memcache error handler so that we don't see internally logged errors.
-    factory().setMemcacheErrorHandler(getConsistentLogAndContinue(Level.INFO));
   }
 
   /** Register translators that allow less common types to be stored directly in Datastore. */