Merge branch 'bw/recurse-submodules-relative-fix'

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