Remove "pull" field from EE mixin

I think this should go on the EE definition itself

awx/api/serializers.py

@@ -649,7 +649,7 @@ class UnifiedJobTemplateSerializer(BaseSerializer):
     class Meta:
         model = UnifiedJobTemplate
         fields = ('*', 'last_job_run', 'last_job_failed',
-                  'next_job_run', 'status', 'execution_environment', 'pull')
+                  'next_job_run', 'status', 'execution_environment')
 
     def get_related(self, obj):
         res = super(UnifiedJobTemplateSerializer, self).get_related(obj)
@@ -716,7 +716,7 @@ class UnifiedJobSerializer(BaseSerializer):
     class Meta:
         model = UnifiedJob
         fields = ('*', 'unified_job_template', 'launch_type', 'status',
-                  'execution_environment', 'pull',
+                  'execution_environment',
                   'failed', 'started', 'finished', 'canceled_on', 'elapsed', 'job_args',
                   'job_cwd', 'job_env', 'job_explanation',
                   'execution_node', 'controller_node',

awx/main/migrations/0124_execution_environments.py

@@ -16,16 +16,6 @@ class Migration(migrations.Migration):
     ]
 
     operations = [
-        migrations.AddField(
-            model_name='unifiedjob',
-            name='pull',
-            field=models.BooleanField(default=True),
-        ),
-        migrations.AddField(
-            model_name='unifiedjobtemplate',
-            name='pull',
-            field=models.BooleanField(default=True),
-        ),
         migrations.CreateModel(
             name='ExecutionEnvironment',
             fields=[

awx/main/models/mixins.py

@@ -454,7 +454,6 @@ class ExecutionEnvironmentMixin(models.Model):
         related_name='%(class)ss',
         help_text=_('The container image to be used for execution.'),
     )
-    pull = models.BooleanField(default=True)
 
 
 class CustomVirtualEnvMixin(models.Model):