Fix submit-row visibility for new objects.
Review Request #11134 — Created Aug. 10, 2020 and submitted
The new change form was using
default_if_noneto specify the defaults
for visibility of various buttons, but that doesn't do the right thing
if the variables being checked just aren't defined at all in the
context. This change fixes it to use
defaultinstead, and enables
visibility of the "Save and add another" and "Save and continue editing"
Opened the admin form for creating new objects (repositories, users,
groups) and saw that the submit row buttons were now visible.