Merge branch 'ab/unused-script-helpers'

Code clean-up.

* ab/unused-script-helpers:
  test-lib: remove unused $_x40 and $_z40 variables
  git-bisect: remove unused SHA-1 $x40 shell variable
  git-sh-setup: remove unused "pull with rebase" message
  git-submodule: remove unused is_zero_oid() function

diff --cc git-submodule.sh
Simple merge

diff --cc t/test-lib.sh
Simple merge