站点的第三方包下载工具有点问题

$ go get -u -v code.google.com/p/cascadia
code.google.com/p/cascadia (download)
Fetching https://golang.org/x/net/html?go-get=1
Parsing meta tags from https://golang.org/x/net/html?go-get=1 (status code 200)
get "golang.org/x/net/html": found meta tag main.metaImport{Prefix:"golang.org/x/net", VCS:"git", RepoRoot:"https://go.googlesource.com/net"} at https://golang.org/x/net/html?go-get=1
get "golang.org/x/net/html": verifying non-authoritative meta tag
Fetching https://golang.org/x/net?go-get=1
Parsing meta tags from https://golang.org/x/net?go-get=1 (status code 200)
package code.google.com/p/cascadia
    imports golang.org/x/net/html: /var/go/gopher/temp/src/golang.org/x/net is from https://code.google.com/p/go.net, should be from https://go.googlesource.com/net
Fetching https://golang.org/x/net/html/atom?go-get=1
Parsing meta tags from https://golang.org/x/net/html/atom?go-get=1 (status code 200)
get "golang.org/x/net/html/atom": found meta tag main.metaImport{Prefix:"golang.org/x/net", VCS:"git", RepoRoot:"https://go.googlesource.com/net"} at https://golang.org/x/net/html/atom?go-get=1
get "golang.org/x/net/html/atom": verifying non-authoritative meta tag
Fetching https://golang.org/x/net?go-get=1
Parsing meta tags from https://golang.org/x/net?go-get=1 (status code 200)
package code.google.com/p/cascadia
    imports golang.org/x/net/html/atom: /var/go/gopher/temp/src/golang.org/x/net is from https://code.google.com/p/go.net, should be from https://go.googlesource.com/net