1.2dev: Simplify code using `setWarningUnsavedChanges`.
1.2dev: Simplify code using `setWarningUnsavedChanges`.

This change also eliminates one translatable string.

Refs #11682.


git-svn-id: eda3d06fcef731589ace1b284159cead3416df9b@14348 af82e41b-90c4-0310-8c96-b1721e28e2e2

walty8/trac,walty8/trac,walty8/trac,walty8/trac