Add a 1-hour expiration to all Objectify memcache uses

This protects us from the edge case of potentially stale
memcache data due to a DeadlineExceededExeption, or possibly
from MemcacheServiceException. If memcache gets stale and
misses a write that went to Datastore, it will catch up in
at most one hour.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=116174023

java/com/google/domain/registry/model/index/DomainApplicationIndex.java

@@ -17,6 +17,7 @@ package com.google.domain.registry.model.index;
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Strings.isNullOrEmpty;
 import static com.google.domain.registry.model.ofy.ObjectifyService.ofy;
+import static com.google.domain.registry.model.ofy.Ofy.RECOMMENDED_MEMCACHE_EXPIRATION;
 import static com.google.domain.registry.util.CollectionUtils.isNullOrEmpty;
 import static com.google.domain.registry.util.DateTimeUtils.latestOf;
 
@@ -43,7 +44,7 @@ import javax.annotation.Nullable;
  * necessary to query them explicitly from Datastore.
  */
 @Entity
-@Cache
+@Cache(expirationSeconds = RECOMMENDED_MEMCACHE_EXPIRATION)
 public class DomainApplicationIndex extends BackupGroupRoot {
 
   @Id