cmd/go: implement svn support in module mode
mod_get_svn passes, and I also tested this manually on a real-world svn-hosted package:
example.com$ go mod init example.com
go: creating new go.mod: module example.com
example.com$ GOPROXY=direct GONOSUMDB=llvm.org go get -d llvm.org/llvm/bindings/go/llvm
go: finding llvm.org/llvm latest
go: finding llvm.org/llvm/bindings/go/llvm latest
go: downloading llvm.org/llvm v0.0.0-
20191022153947-
000000375505
go: extracting llvm.org/llvm v0.0.0-
20191022153947-
000000375505
example.com$ go list llvm.org/llvm/bindings/...
llvm.org/llvm/bindings/go
llvm.org/llvm/bindings/go/llvm
Fixes #26092
Change-Id: Iefe2151b82a0225c73bb6f8dd7cd8a352897d4c0
Reviewed-on: https://go-review.googlesource.com/c/go/+/203497
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>