protoc-gen-go: remove relative import in main_test.go (#535)
protoc-gen-go: remove relative import in main_test.go (#535)

No particular reason for this to be a ./ import, and it confuses vgo.
golang/protobuf,fuchsia-mirror/third_party-github.com-golang-protobuf,fuchsia-mirror/third_party-github.com-golang-protobuf,golang/protobuf