builder/docker: allow DOCKER_HOST

CHANGELOG.md

@@ -7,6 +7,8 @@ FEATURES:
 IMPROVEMENTS:
 
   * builder/amazon/all: Support new AWS Frankfurt region.
+  * builder/docker: Allow remote `DOCKER_HOST`, which works as long as
+      volumes work. [GH-1594]
 
 BUG FIXES:
 

builder/docker/driver_docker.go

@@ -258,10 +258,5 @@ func (d *DockerDriver) Verify() error {
 		return err
 	}
 
-	if v := os.Getenv("DOCKER_HOST"); v != "" {
-		return fmt.Errorf(
-			"DOCKER_HOST cannot be set with the Packer Docker builder.")
-	}
-
 	return nil
 }