Merge branch 'pk/status-of-uncloned-submodule'

Merge branch 'pk/status-of-uncloned-submodule'

The way "git submodule status" reports an initialized but not yet
populated submodule has not been reimplemented correctly when a
part of the "git submodule" command was rewritten in C, which has
been corrected.

* pk/status-of-uncloned-submodule:
  t7400: testcase for submodule status on unregistered inner git repos
  submodule: fix status of initialized but not cloned submodules
  t7400: add a testcase for submodule status on empty dirs