Skip git submodule scan when there is no .gitmodules

`projectile-get-immediate-sub-projects' was unconditionally shelling
out to `git submodule --quiet foreach ...' on every indexing call for
git projects, even when the project had no submodules at all. For
monorepos that re-index the project root often this is pure overhead.

Use `locate-dominating-file' to look for `.gitmodules' along the
parent chain (PATH may be inside a git repo without being its
toplevel) and skip the shell-out when none is found.

Also tighten `projectile-discover-projects-in-directory' to filter
`.' / `..' via `directory-files-no-dot-files-regexp' instead of a
post-filter `member' check, matching the indexing walker's style.

0 files changed, 0 insertions, 0 deletions