bootstrap.sh: Fix naming origin

Created by: genodeftest

Problem: By default, running bootstrap.sh doesn't work because in line 386, origin repo is named upstream, but in line 408 it was called "origin".

Solution: Always name origin "upstream"

Drawbacks: Breaks updating your local repository from upstream if you named origin repo "origin".

TODOs: Nothing

State: ready

Blocking/related: None