Remove old json logging from flows

This was meant for log replay and has long been ignored/useless.
As part of this, remove execution time from EppResponse since this
was the only thing consuming it.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=137293734

java/google/registry/model/eppoutput/EppResponse.java

@@ -68,9 +68,7 @@ import javax.xml.bind.annotation.XmlElement;
 import javax.xml.bind.annotation.XmlElementRef;
 import javax.xml.bind.annotation.XmlElementRefs;
 import javax.xml.bind.annotation.XmlElementWrapper;
-import javax.xml.bind.annotation.XmlTransient;
 import javax.xml.bind.annotation.XmlType;
-import org.joda.time.DateTime;
 
 /**
  * The EppResponse class represents an EPP response message.
@@ -91,14 +89,6 @@ public class EppResponse extends ImmutableObject implements ResponseOrGreeting {
   /** The command result. The RFC allows multiple failure results, but we always return one. */
   Result result;
 
-  /**
-   * The time the command that created this response was executed.
-   *
-   * <p>This is for logging purposes only and is not returned to the user.
-   */
-  @XmlTransient
-  DateTime executionTime;
-
   /**
    * Information about messages queued for retrieval. This may appear in response to any EPP message
    * (if messages are queued), but in practice this will only be set in response to a poll request.
@@ -158,10 +148,6 @@ public class EppResponse extends ImmutableObject implements ResponseOrGreeting {
   @XmlElementWrapper(name = "extension")
   ImmutableList<? extends ResponseExtension> extensions;
 
-  public DateTime getExecutionTime() {
-    return executionTime;
-  }
-
   public ImmutableList<? extends ResponseData> getResponseData() {
     return resData;
   }
@@ -221,11 +207,6 @@ public class EppResponse extends ImmutableObject implements ResponseOrGreeting {
       return this;
     }
 
-    public Builder setExecutionTime(DateTime executionTime) {
-      getInstance().executionTime = executionTime;
-      return this;
-    }
-
     public Builder setResData(@Nullable ImmutableList<? extends ResponseData> resData) {
       getInstance().resData = resData;
       return this;