Replace utils.CheckLocalDns with bytes.Contains line

Since RemoveLocalDns patch will  remove all localhost entries
from resolv.conf we no longer need anything more then
!bytes.Contains(resolvConf, []byte("nameserver")

To check for no nameserver entry in dns config.

Docker-DCO-1.1-Signed-off-by: Dan Walsh <dwalsh@redhat.com> (github: rhatdan)
Upstream-commit: a297d6ab8c08a13503fd004ec1ad7ee9e23bd22a
Component: engine

components/engine/utils/utils.go

@@ -313,26 +313,6 @@ func IsGIT(str string) bool {
 	return strings.HasPrefix(str, "git://") || strings.HasPrefix(str, "github.com/") || strings.HasPrefix(str, "git@github.com:") || (strings.HasSuffix(str, ".git") && IsURL(str))
 }
 
-// CheckLocalDns looks into the /etc/resolv.conf,
-// it returns true if there is a local nameserver or if there is no nameserver.
-func CheckLocalDns(resolvConf []byte) bool {
-	for _, line := range GetLines(resolvConf, []byte("#")) {
-		if !bytes.Contains(line, []byte("nameserver")) {
-			continue
-		}
-		for _, ip := range [][]byte{
-			[]byte("127.0.0.1"),
-			[]byte("127.0.1.1"),
-		} {
-			if bytes.Contains(line, ip) {
-				return true
-			}
-		}
-		return false
-	}
-	return true
-}
-
 var (
 	localHostRx = regexp.MustCompile(`(?m)^nameserver 127[^\n]+\n*`)
 )
@@ -343,21 +323,6 @@ func RemoveLocalDns(resolvConf []byte) []byte {
 	return localHostRx.ReplaceAll(resolvConf, []byte{})
 }
 
-// GetLines parses input into lines and strips away comments.
-func GetLines(input []byte, commentMarker []byte) [][]byte {
-	lines := bytes.Split(input, []byte("\n"))
-	var output [][]byte
-	for _, currentLine := range lines {
-		var commentIndex = bytes.Index(currentLine, commentMarker)
-		if commentIndex == -1 {
-			output = append(output, currentLine)
-		} else {
-			output = append(output, currentLine[:commentIndex])
-		}
-	}
-	return output
-}
-
 // An StatusError reports an unsuccessful exit by a command.
 type StatusError struct {
 	Status     string