Update to git version v2.7.0.
* Upstream commit
ed1c9977cb1b63e4270ad8bdf967a2d02580aa08 (Remove
get_object_hash.) changed API:
Convert all instances of get_object_hash to use an appropriate
reference to the hash member of the oid member of struct object.
This provides no functional change, as it is essentially a macro
substitution.
Signed-off-by: Christian Hesse <mail@eworm.de>