Remove headless option as it is not used.

builder/hyperv/common/run_config.go

@@ -7,7 +7,6 @@ import (
 )
 
 type RunConfig struct {
-	Headless    bool   `mapstructure:"headless"`
 	RawBootWait string `mapstructure:"boot_wait"`
 
 	BootWait time.Duration ``

builder/hyperv/common/step_run.go

@@ -13,7 +13,6 @@ import (
 
 type StepRun struct {
 	BootWait time.Duration
-	Headless bool
 
 	vmName string
 }

builder/hyperv/iso/builder.go

@@ -364,7 +364,6 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 
 		&hypervcommon.StepRun{
 			BootWait: b.config.BootWait,
-			Headless: b.config.Headless,
 		},
 
 		&hypervcommon.StepTypeBootCommand{