gddo-server: Block the domain name zxq.co

We recently saw about 50K new packages from this domain. The packages
are all go-getable but appear to be spams. The contents fetched from gddo
or 'go get' are different than what the web host shows. We are blocking
this domain for now and investigating.

Change-Id: I9d3aa55366362941e66c8caea9b855ab1de65d7c
Reviewed-on: https://go-review.googlesource.com/42950
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
1 file changed