The 'git receive-pack' command has been updated to use a new ODB
transaction interface for writing incoming packfiles, making it more
backend-agnostic.
* jt/receive-pack-pluggable-writes:
odb/transaction: add transaction interface to write packfiles
odb: return temporary ODB source when set
builtin/receive-pack: explicitly pass packfile fd
builtin/receive-pack: report unpack errors via strbuf
builtin/receive-pack: lift global state out of unpack()
builtin/receive-pack: read unpack limit config lazily
builtin/receive-pack: pass shallow file explicitly
odb/transaction: add transaction finalize interface
builtin/receive-pack: properly clean up keep files