[#350] Track correct upstream branch on clone
[#350] Track correct upstream branch on clone

This fixes a bug where if:

(1) you specified both an upstream and a fork
(2) both the upstream and a fork have a branch by the same name
(3) your recipe tells straight.el to use that branch for your local
    work

then your local branch is set up to track the upstream branch rather
than the fork branch as it is supposed to.

raxod502/straight.el,raxod502/straight.el