sh-i18n--envsubst: retire unused string_list_member()
sh-i18n--envsubst: retire unused string_list_member()

This static function has no callers, nor has it had any since its
introduction in ba67aaf2d05d (git-sh-i18n--envsubst: our own envsubst(1)
for eval_gettext(), 2011-05-14). Remove it.

Signed-off-by: Eric Sunshine <8d6e34f987851aa599257d3831a1af040886842f@sunshineco.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git