Only allow http/https schemas for image download

Glance only supports http/https image urls, but default django URLField
allows ftp/ftps images to be entered. This commit adds validator, that
restricts schema to http/https

Change-Id: I1e9ddbc82a0a6aaaf1322f7e8f89dfe5f79bf260
Related-Bug: #1467787

openstack_dashboard/dashboards/project/images/images/forms.py

@@ -19,7 +19,9 @@
 """
 Views for managing images.
 """
+
 from django.conf import settings
+from django.core import validators
 from django.forms import ValidationError  # noqa
 from django.forms.widgets import HiddenInput  # noqa
 from django.template import defaultfilters
@@ -102,6 +104,8 @@ class CreateImageForm(forms.SelfHandlingForm):
                                    'ng-model': 'copyFrom',
                                    'ng-change':
                                    'ctrl.selectImageFormat(copyFrom)'}),
+                               validators=[validators.URLValidator(
+                                   schemes=["http", "https"])],
                                required=False)
     image_file = forms.FileField(label=_("Image File"),
                                  help_text=_("A local image to upload."),