Describe the bug

The way I use git is to stay in "detached HEAD," except when working on my own feature branches. For example, I don't keep a local master branch, and instead just refer to origin/master as necessary.

This breaks gh:

➜ gh --version
gh version DEV
https://github.com/cli/cli/releases/latest

➜ gh pr status
could not query for pull request for current branch: could not determine current branch: git: not on any branch

I built the tool via go install github.com/cli/cli/cmd/gh on the current latest commit (28f91cb).

Expected vs actual behavior

See above console output for actual behavior. What I expect is something like the following:

➜ gh pr status

Relevant pull requests in <REPO>

Current branch
  could not query for pull request for current branch: could not determine current branch: git: not on any branch

Created by you
  ...

Requesting a code review from you
  ...

Note that the error about not being on a branch is only relevant for the "current branch" section, so the gh tool should still output the other sections.