Module component refs are lost when dumping the object to a string

[mprahl]

If I have a module component that has a ref specified, the ref is lost when I dump the module to a string.

Here is the reproducer in Python:

>>> import gi
>>> gi.require_version('Modulemd', '1.0')
>>> from gi.repository import Modulemd
>>> mmd = Modulemd.Module().new_from_string("""
... document: modulemd
... version: 1
... data:
...     summary: A test module in all its beautiful beauty.
...     description: This module demonstrates how to write simple modulemd files And can be used for testing the build and release pipeline.
...     license:
...         module: [ MIT ]
...     dependencies:
...         buildrequires:
...             platform: el8
...         requires:
...             platform: el8
...     references:
...         community: https://fedoraproject.org/wiki/Modularity
...         documentation: https://fedoraproject.org/wiki/Fedora_Packaging_Guidelines_for_Modules
...         tracker: https://taiga.fedorainfracloud.org/project/modularity
...     profiles:
...         default:
...             rpms:
...                 - acl
...     api:
...         rpms:
...             - acl
...     components:
...         rpms:
...             acl:
...                 rationale: needed
...                 ref: rhel-8.0
...         modules:
...             testmodule:
...                 ref: private-x
...                 rationale: Testing module inclusion.
...                 buildorder: 10
... """)
>>> assert mmd.get_module_components()['testmodule'].get_ref() == 'private-x'
>>> mmd2 = Modulemd.Module().new_from_string(mmd.dumps())
>>> assert mmd2.get_module_components()['testmodule'].get_ref() == 'private-x'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AssertionError

[sgallagher]

Turns out there was a copy-paste error in the YAML output and I was writing the repository value to the ref. Oops. PR is out.