Merge pull request #4168 from mitchellh/noerrorsess

fix new session error when creating cred chain.

builder/amazon/common/access_config.go

@@ -45,10 +45,6 @@ func (c *AccessConfig) Config() (*aws.Config, error) {
 			return nil, err
 		}
 	} else {
-		session, err := session.NewSession(config)
-		if err != nil {
-			return nil, err
-		}
 		creds = credentials.NewChainCredentials([]credentials.Provider{
 			&credentials.StaticProvider{Value: credentials.Value{
 				AccessKeyID:     c.AccessKey,
@@ -58,7 +54,7 @@ func (c *AccessConfig) Config() (*aws.Config, error) {
 			&credentials.EnvProvider{},
 			&credentials.SharedCredentialsProvider{Filename: "", Profile: ""},
 			&ec2rolecreds.EC2RoleProvider{
-				Client: ec2metadata.New(session),
+				Client: ec2metadata.New(session.New(config)),
 			},
 		})
 	}