Merge branch 'jk/startup-info'
The startup_info data, which records if we are working inside a
repository (among other things), are now uniformly available to Git
subcommand implementations, and Git avoids attempting to touch
references when we are not in a repository.
* jk/startup-info:
use setup_git_directory() in test-* programs
grep: turn off gitlink detection for --no-index
mailmap: do not resolve blobs in a non-repository
remote: don't resolve HEAD in non-repository
setup: set startup_info->have_repository more reliably
setup: make startup_info available everywhere