package/bash: remove dead comment

Commit 02e5cef1 (system: add option to choose what /bin/sh points to)
removed the symlink creation, but forgot to remove the corresponding
comment, which is now more puzzling than amusing...

Remove the comment.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Romain Naour <romain.naour@gmail.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>