Merge branch 'bw/grep-recurse-submodules' into bw/submodule-config-cleanup

* bw/grep-recurse-submodules: grep: recurse in-process using 'struct repository' submodule: merge repo_read_gitmodules and gitmodules_config submodule: check for unmerged .gitmodules outside of config parsing submodule: check for unstaged .gitmodules outside of config parsing submodule: remove fetch.recursesubmodules from submodule-config parsing submodule: remove submodule.fetchjobs from submodule-config parsing config: add config_from_gitmodules cache.h: add GITMODULES_FILE macro repository: have the_repository use the_index repo_read_index: don't discard the index