review: copying .gitattributes to all subrepositories
review: copying .gitattributes to all subrepositories

Fixes #9281

Change-Id: Iae395834b5eb0d5709a22ac78949d274fed77c93
Reviewed-on: https://go-review.googlesource.com/2078
Reviewed-by: Minux Ma <72d850dbd8858b791995463d8539b5a379577f28@golang.org>

golang/review,Go-zh/review