Save the RDAP request time globally instead of passing it around

Also removed the rdapWhoisServer value, as it's just null and will likely stay that way (it isn't mentioned in the RDAP response profile)

If it'll ever become required, we can add it back.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=247643981

java/google/registry/rdap/RdapNameserverAction.java

@@ -31,7 +31,6 @@ import google.registry.request.HttpException.NotFoundException;
 import google.registry.request.auth.Auth;
 import java.util.Optional;
 import javax.inject.Inject;
-import org.joda.time.DateTime;
 
 /** RDAP (new WHOIS) action for nameserver requests. */
 @Action(
@@ -48,7 +47,6 @@ public class RdapNameserverAction extends RdapActionBase {
 
   @Override
   public RdapNameserver getJsonObjectForResource(String pathSearchString, boolean isHeadRequest) {
-    DateTime now = clock.nowUtc();
     pathSearchString = canonicalizeName(pathSearchString);
     // The RDAP syntax is /rdap/nameserver/ns1.mydomain.com.
     try {
@@ -63,11 +61,12 @@ public class RdapNameserverAction extends RdapActionBase {
     // the most recently deleted one.
     Optional<HostResource> hostResource =
         loadByForeignKey(
-            HostResource.class, pathSearchString, shouldIncludeDeleted() ? START_OF_TIME : now);
-    if (!shouldBeVisible(hostResource, now)) {
+            HostResource.class,
+            pathSearchString,
+            shouldIncludeDeleted() ? START_OF_TIME : getRequestTime());
+    if (!shouldBeVisible(hostResource)) {
       throw new NotFoundException(pathSearchString + " not found");
     }
-    return rdapJsonFormatter.makeRdapJsonForHost(
-        hostResource.get(), rdapWhoisServer, now, OutputDataType.FULL);
+    return rdapJsonFormatter.makeRdapJsonForHost(hostResource.get(), OutputDataType.FULL);
   }
 }