I'm unable to save the settings on a per-project basis

To reproduce the use:

1) From the "Configure System" screen select "Project-based Matrix Authorization
Strategy"
2) From the project configuration screen select "Enabled project-based security"
3) On the Anonymous user settings enable "build"
4) hit save.

Nothing is written to the project build.xml file to indicate which settings were
selected (build should be saved) to save although the useProjectSecurity XML
element is defined and set to "true".