Improve readability of saving glue code

Summary:
Instead of two calls to doSave* with different boolean values, we can
simply pass the bool directly. This makes the code easier to understand.

Test Plan:
Save and Save As should work as before with any state of
Quit after Save or Copy.

Reviewers: Spectacle, ngraham

Reviewed By: Spectacle, ngraham

Subscribers: ngraham

Differential Revision: https://phabricator.kde.org/D13244