Unexpected Behaviour renaming nested workflow as the step name

I am running the dummy [nested workflow example](http://www.commonwl.org/user_guide/22-nested-workflows/) from the user guide which is running the [1st workflow example](http://www.commonwl.org/user_guide/21-1st-workflow/) as nested workflow.

## Expected Behavior
The nested workflow should have be referred by its name in the logged info:
```
[workflow nested-workflow.cwl] starting step compile
[step compile] start
[workflow 1st-workflow.cwl] start
[workflow 1st-workflow.cwl] starting step untar
[step untar] start
```

## Actual Behavior
The outer step name is used as nested workflow name:
```
[workflow nested-workflow.cwl] starting step compile
[step compile] start
[workflow compile] start
[workflow compile] starting step untar
[step untar] start
```

## Workflow Code
```
#!/usr/bin/env cwl-runner

cwlVersion: v1.0
class: Workflow

inputs: []

outputs:
classout:
type: File
outputSource: compile/classout

requirements:
- class: SubworkflowFeatureRequirement

steps:
compile:
run: 1st-workflow.cwl
in:
inp:
source: create-tar/tar
ex:
default: "Hello.java"
out: [classout]

create-tar:
requirements:
- class: InitialWorkDirRequirement
listing:
- entryname: Hello.java
entry: |
public class Hello {
public static void main(String[] argv) {
System.out.println("Hello from Java");
}
}
in: []
out: [tar]
run:
class: CommandLineTool
requirements:
- class: ShellCommandRequirement
arguments:
- shellQuote: false
valueFrom: |
date
tar cf hello.tar Hello.java
date
inputs: []
outputs:
tar:
type: File
outputBinding:
glob: "hello.tar"

```
## Your Environment
* cwltool version: 1.0.20180403145700