Revert "Add extra tools to the rescue image"

This reverts commit c7deb3988cbd01c34c79aaa7c4182aabbb5c92df.

This is not needed, because the extra tools were added
to the FreeNAS build/create_iso.sh script in b62da2ce813980107859e319cd4a174201aed683 .
In future, if we need to add new binaries to the install ISO, we should
add them in build/create_iso.sh instead of adding to the rescue image.

This minimizes differences to FreeBSD.