helper: communicator.SSHFileSigner => ssh.FileSigner

* had to to avoid circular dependency
* this commit fixes #6631 ( esxi cannot be reached by ssh )

builder/vmware/iso/driver_esx5.go

@@ -17,6 +17,7 @@ import (
 	vmwcommon "github.com/hashicorp/packer/builder/vmware/common"
 	"github.com/hashicorp/packer/communicator/ssh"
 	"github.com/hashicorp/packer/helper/multistep"
+	helperssh "github.com/hashicorp/packer/helper/ssh"
 	"github.com/hashicorp/packer/packer"
 	gossh "golang.org/x/crypto/ssh"
 )
@@ -514,7 +515,7 @@ func (d *ESX5Driver) connect() error {
 	}
 
 	if d.PrivateKey != "" {
-		signer, err := gossh.ParsePrivateKey([]byte(d.PrivateKey))
+		signer, err := helperssh.FileSigner(d.PrivateKey)
 		if err != nil {
 			return err
 		}

helper/communicator/config.go

@@ -10,6 +10,7 @@ import (
 
 	packerssh "github.com/hashicorp/packer/communicator/ssh"
 	"github.com/hashicorp/packer/helper/multistep"
+	helperssh "github.com/hashicorp/packer/helper/ssh"
 	"github.com/hashicorp/packer/template/interpolate"
 	"github.com/masterzen/winrm"
 	"golang.org/x/crypto/ssh"
@@ -241,7 +242,7 @@ func (c *Config) prepareSSH(ctx *interpolate.Context) []error {
 		if _, err := os.Stat(c.SSHPrivateKeyFile); err != nil {
 			errs = append(errs, fmt.Errorf(
 				"ssh_private_key_file is invalid: %s", err))
-		} else if _, err := SSHFileSigner(c.SSHPrivateKeyFile); err != nil {
+		} else if _, err := helperssh.FileSigner(c.SSHPrivateKeyFile); err != nil {
 			errs = append(errs, fmt.Errorf(
 				"ssh_private_key_file is invalid: %s", err))
 		}

helper/communicator/step_connect_ssh.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/hashicorp/packer/communicator/ssh"
 	"github.com/hashicorp/packer/helper/multistep"
+	helperssh "github.com/hashicorp/packer/helper/ssh"
 	"github.com/hashicorp/packer/packer"
 	gossh "golang.org/x/crypto/ssh"
 	"golang.org/x/crypto/ssh/agent"
@@ -225,7 +226,7 @@ func sshBastionConfig(config *Config) (*gossh.ClientConfig, error) {
 	}
 
 	if config.SSHBastionPrivateKey != "" {
-		signer, err := gossh.ParsePrivateKey([]byte(config.SSHBastionPrivateKey))
+		signer, err := helperssh.FileSigner(config.SSHBastionPrivateKey)
 		if err != nil {
 			return nil, err
 		}

helper/ssh/ssh.go

@@ -1,4 +1,4 @@
-package communicator
+package ssh
 
 import (
 	"encoding/pem"
@@ -9,8 +9,8 @@ import (
 	"golang.org/x/crypto/ssh"
 )
 
-// SSHFileSigner returns an ssh.Signer for a key file.
-func SSHFileSigner(path string) (ssh.Signer, error) {
+// FileSigner returns an ssh.Signer for a key file.
+func FileSigner(path string) (ssh.Signer, error) {
 	f, err := os.Open(path)
 	if err != nil {
 		return nil, err