protoc-gen-go: fix test (#545)

Broken by addition of GoImportPath/GoPackageName.

protoc-gen-go/generator/name_test.go

@@ -59,9 +59,10 @@ func TestCamelCase(t *testing.T) {
 
 func TestGoPackageOption(t *testing.T) {
 	tests := []struct {
-		in           string
-		impPath, pkg string
-		ok           bool
+		in      string
+		impPath GoImportPath
+		pkg     GoPackageName
+		ok      bool
 	}{
 		{"", "", "", false},
 		{"foo", "", "foo", true},