repository: add a helper function to perform repository format upgrade
In version 1 of repository format, "extensions" gained special meaning
and it is safer to avoid upgrading when there are pre-existing
extensions.
Make list-objects-filter to use the helper function instead of setting
repository version directly as a prerequisite of exposing the upgrade
capability.
Signed-off-by: Xin Li <delphij@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
projects / thirdparty / git.git / commit
