regexp: fix imports in the middle of the license header
regexp: fix imports in the middle of the license header

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/129620043

Committer: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

wesolows/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,wesolows/golang,wesolows/golang-old,wesolows/golang,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,wesolows/golang,wesolows/golang