Add fields missing from CREATE_IMAGE_FORM_FIELDS and are present on actual page.
Reason of test failing is that image creation form of horizon is differ
from the one described in the pageobject. Adding fields to
CREATE_IMAGE_FORM_FIELDS fixes test.
Closes-Bug: #1464651
Partially implements blueprint: selenium-integration-testing
Change-Id: I6baf6c1918f37cb3b6009919bfbe9615c336a101