archive/zip: use bufio.Reset rather than NewReader
A clean up for CL 408734, suggested by Joe Tsai.
Change-Id: Ida9db0b8d31785d5640938c286c9c6c82c27f457
Reviewed-on: https://go-review.googlesource.com/c/go/+/410154
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Joseph Tsai <joetsai@digital-static.net>