fix bug #9703 parse error

Outputs the name of the file with a parsing error (more details in #9703)
```
$ ansible-playbook -i ../local_only_inventory --syntax-check *.yml
```
old output:
```
playbook: a.yml

ERROR: parse error: playbooks must be formatted as a YAML list, got <type 'dict'>
```
New output:
```
playbook: a.yml

ERROR: b.yml
parse error: playbooks must be formatted as a YAML list, got <type 'dict'>
```