R1:d1eed54d85bc

Fix expansion of projects into lists of user PHIDs

Summary:
Ref T11016. I think I inverted the meaning of this function by accident in D14893.

The intent is to return a list of users: direct users, and all members of all projects.

Prior to this patch actually returns direct users, and all projects they are members of.

Test Plan:
- Created "Project with Dog".
- Added user "dog" to project.
- Created package "X", owning file "/x", with audit enabled.
- Made "X" owned by "Project with Dog".