Replace references to several hard-coded object IDs with a variable
referring to the generated commit. Avoid matching on exact character
positions, which will be different depending on the hash in use. In the
test for a valid object ID, use an obviously invalid one from the lookup
table.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>