cmd/api: always do API check if hg is available

Fixes #6124

R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/13500046

src/cmd/api/run.go

@@ -21,7 +21,6 @@ import (
 	"os/exec"
 	"os/user"
 	"path/filepath"
-	"strconv"
 	"strings"
 )
 
@@ -38,9 +37,9 @@ func main() {
 	if goroot == "" {
 		log.Fatal("No $GOROOT set.")
 	}
-	isGoDeveloper := exec.Command("hg", "pq").Run() == nil
-	if !isGoDeveloper && !forceAPICheck() {
-		fmt.Println("Skipping cmd/api checks; hg codereview extension not available and GO_FORCE_API_CHECK not set")
+	_, err := exec.LookPath("hg")
+	if err != nil {
+		fmt.Println("Skipping cmd/api checks; hg not available")
 		return
 	}
 
@@ -88,12 +87,6 @@ func file(s ...string) string {
 	return filepath.Join(goroot, "api", s[0]+".txt")
 }
 
-// GO_FORCE_API_CHECK is set by builders.
-func forceAPICheck() bool {
-	v, _ := strconv.ParseBool(os.Getenv("GO_FORCE_API_CHECK"))
-	return v
-}
-
 // prepGoPath returns a GOPATH for the "go" tool to compile the API tool with.
 // It tries to re-use a go.tools checkout from a previous run if possible,
 // else it hg clones it.