Fix git-fast-export for zero-sized blobs
Fix git-fast-export for zero-sized blobs

Writing 1 elements of size 0-byte successfully will cause fwrite(3) to
return 0, and flagging it as error is a mistake.

Signed-off-by: Alex Riesen <053ce55f4869b7f450d1d77b8f162c6f2bb9e137@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

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