Respond to code review feedback.

openedx/core/djangoapps/credit/api.py

@@ -267,8 +267,6 @@ def create_credit_request(course_key, provider_id, username):
 
     if created:
         credit_request.uuid = uuid.uuid4().hex
-    else:
-        credit_request.timestamp = datetime.datetime.now(pytz.UTC)
 
     # Retrieve user account and profile info
     user = User.objects.select_related('profile').get(username=username)
@@ -291,7 +289,7 @@ def create_credit_request(course_key, provider_id, username):
 
     parameters = {
         "request_uuid": credit_request.uuid,
-        "timestamp": to_timestamp(credit_request.timestamp),
+        "timestamp": to_timestamp(datetime.datetime.now(pytz.UTC)),
         "course_org": course_key.org,
         "course_num": course_key.course,
         "course_run": course_key.run,

openedx/core/djangoapps/credit/models.py

@@ -14,7 +14,6 @@ from django.core.validators import RegexValidator
 from simple_history.models import HistoricalRecords
 
 from jsonfield.fields import JSONField
-from util.date_utils import to_timestamp
 from model_utils.models import TimeStampedModel
 from xmodule_django.models import CourseKeyField
 from django.utils.translation import ugettext_lazy
@@ -343,7 +342,6 @@ class CreditRequest(TimeStampedModel):
     username = models.CharField(max_length=255, db_index=True)
     course = models.ForeignKey(CreditCourse, related_name="credit_requests")
     provider = models.ForeignKey(CreditProvider, related_name="credit_requests")
-    timestamp = models.DateTimeField(auto_now_add=True)
     parameters = JSONField()
 
     REQUEST_STATUS_PENDING = "pending"
@@ -393,7 +391,7 @@ class CreditRequest(TimeStampedModel):
         return [
             {
                 "uuid": request.uuid,
-                "timestamp": to_timestamp(request.modified),
+                "timestamp": request.parameters.get("timestamp"),
                 "course_key": request.course.course_key,
                 "provider": {
                     "id": request.provider.provider_id,