Several of our shell scripts hard-code the object ID of the empty tree.
To avoid any problems when changing hashes, compute this value on
startup of the script. For performance, store the value in a variable
and reuse it throughout the life of the script.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>