upload-pack: Run rev-list in an asynchronous function.
upload-pack: Run rev-list in an asynchronous function.

This gets rid of an explicit fork().

Since upload-pack has to coordinate two processes (rev-list and
pack-objects), we cannot use the normal finish_async(), but have to monitor
the process explicitly. Hence, there are no changes at this front.

Signed-off-by: Johannes Sixt <5cc107486946fdcf16e86d7c808fa50f4312125f@telecom.at>
Signed-off-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git