Merge branch 'bc/submodule-foreach-stdin-fix-1.7.4' into maint

* bc/submodule-foreach-stdin-fix-1.7.4:
  git-submodule.sh: preserve stdin for the command spawned by foreach
  t/t7407: demonstrate that the command called by 'submodule foreach' loses stdin

diff --cc git-submodule.sh
Simple merge

diff --cc t/t7407-submodule-foreach.sh
Simple merge