Editing the "Add builds" section of a permission causes access to be wiped

Symptoms: Builds that used to work now return a 403 error on uploads of the buildinfo.json file.

Cause: When adding or changing all the builds in a permission, it causes the user to lose all build access.

Steps to reproduce:

1. Start with a build permission set that grants the user access to build information
2. Remove all builds from the permission target - Don't click save
3. Re-add any build name
4. Recheck the user's permissions again, the build permissions are all now gone

If the user saves the permission after modifying the builds section, they have effectively revoked all build access in the permission.

This applies especially to builds; many times an Admin will replace the default "all builds" with a more specific permission set. Editing or removing the entire set can cause unexpected build failures.

The same behavior can be seen in Repository permissions as well. Removing all repositories from a permission set wipes all repo-based permission configurations.