* jk/submodule-fsck-loose:
fsck: complain when .gitmodules is a symlink
index-pack: check .gitmodules files with --strict
unpack-objects: call fsck_finish() after fscking objects
fsck: call fsck_finish() after fscking objects
fsck: check .gitmodules content
fsck: handle promisor objects in .gitmodules check
fsck: detect gitmodules files
fsck: actually fsck blob data
fsck: simplify ".git" check
index-pack: make fsck error message more specific