Use filepath when manipulating file paths (#2221)

Automatically submitted.

plugin/file/setup.go

@@ -2,7 +2,7 @@ package file
 
 import (
 	"os"
-	"path"
+	"path/filepath"
 	"time"
 
 	"github.com/coredns/coredns/core/dnsserver"
@@ -71,8 +71,8 @@ func fileParse(c *caddy.Controller) (Zones, error) {
 			origins = args
 		}
 
-		if !path.IsAbs(fileName) && config.Root != "" {
-			fileName = path.Join(config.Root, fileName)
+		if !filepath.IsAbs(fileName) && config.Root != "" {
+			fileName = filepath.Join(config.Root, fileName)
 		}
 
 		reader, err := os.Open(fileName)

plugin/file/zone.go

@@ -3,7 +3,7 @@ package file
 import (
 	"fmt"
 	"net"
-	"path"
+	"path/filepath"
 	"strings"
 	"sync"
 	"time"
@@ -48,7 +48,7 @@ func NewZone(name, file string) *Zone {
 	z := &Zone{
 		origin:         dns.Fqdn(name),
 		origLen:        dns.CountLabel(dns.Fqdn(name)),
-		file:           path.Clean(file),
+		file:           filepath.Clean(file),
 		Tree:           &tree.Tree{},
 		Expired:        new(bool),
 		reloadShutdown: make(chan bool),