Make service URLs optional on programs config model

We're moving away from this config model and no longer need to specify these URLs.

ECOM-4422

openedx/core/djangoapps/programs/migrations/0010_auto_20170204_2332.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('programs', '0009_programsapiconfig_marketing_path'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='programsapiconfig',
+            name='internal_service_url',
+            field=models.URLField(verbose_name='Internal Service URL', blank=True),
+        ),
+        migrations.AlterField(
+            model_name='programsapiconfig',
+            name='public_service_url',
+            field=models.URLField(verbose_name='Public Service URL', blank=True),
+        ),
+    ]

openedx/core/djangoapps/programs/models.py

@@ -19,8 +19,8 @@ class ProgramsApiConfig(ConfigurationModel):
 
     api_version_number = models.IntegerField(verbose_name=_("API Version"))
 
-    internal_service_url = models.URLField(verbose_name=_("Internal Service URL"))
-    public_service_url = models.URLField(verbose_name=_("Public Service URL"))
+    internal_service_url = models.URLField(verbose_name=_("Internal Service URL"), blank=True)
+    public_service_url = models.URLField(verbose_name=_("Public Service URL"), blank=True)
 
     marketing_path = models.CharField(
         max_length=255,