Merge branch 'jk/fetch-pack-avoid-sigpipe-to-index-pack'

"git fetch", when received a bad packfile, can fail with SIGPIPE. This wasn't wrong per-se, but we now detect the situation and fail in a more predictable way. * jk/fetch-pack-avoid-sigpipe-to-index-pack: fetch-pack: ignore SIGPIPE when writing to index-pack