Don't treat git local remotes as "remote"

When creating a branch with `git checkout -t -b BRANCH`, the upstream
"remote" is the starting branch on disk, so a command like
`config --get branch.$current_branch.remote` returns "."
In this case the "remote" isn't really "remote," so we shouldn't try to
query an upstream system to determine whether code has been sync'd to
the remote.

This has been trolling me because it makes tests fail locally when working on a branch that tracks local master (e.g., `git checkout -t -b my-feature`).

@opscode/client-engineers