If object reuse validation is enabled, the output pack is going to
probably be stored locally. When reusing an existing cached pack
to save object enumeration costs, ensure the cached pack has not
been corrupted by checking its SHA-1 trailer. If it has, writing
will abort and the output pack won't be complete. This prevents
anyone from trying to use the output pack, and catches corruption
before it can be carried any further.
Change-Id: If89d0d4e429d9f4c86f14de6c0020902705153e6
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
a468cb57c2