Code review comment for ~azzar1/ubiquity:fix_regain_privileges_save

> @vanvugt: I think ubiquity just moved to git
>
> From my comments on IRC:
>
> I don't understand why we don't call directly os.setresuid(0, egid, 0) for
> instance. This is probably because os.setgroups([]) has an incidence, but I've
> never used that one
>
> Preservering the euid and geuid is needed for sure and replacing with 0 for
> uid/guid was a mistake
> but I don't understand why the calls in 2 steps. Do you mind expanding (and
> adding a comment?)

From https://git.launchpad.net/ubiquity/commit/?id=815fbf12 : "Set the effective UID in regain_privileges_save so we don't try to setgroups([]) as a regular user (LP: #646827)."