A few commands that recently learned the "--recurse-submodule"
option misbehaved when started from a subdirectory of the
superproject.
* bw/recurse-submodules-relative-fix:
ls-files: fix bug when recursing with relative pathspec
ls-files: fix typo in variable name
grep: fix bug when recursing with relative pathspec
setup: allow for prefix to be passed to git commands
grep: fix help text typo