See: https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.0.TXT

Document says:
> If general purpose bit 11 is set, the filename and comment must support The
> Unicode Standard, Version 4.1.0 or greater using the character encoding form
> defined by the UTF-8 storage specification.

Since Go encode the filename to UTF-8, general purpose bit 11 should be set.

Change-Id: Ica4af02b4dc695e9a5c015ae360e70171efb6ee3
Reviewed-on: https://go-review.googlesource.com/39570Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>