Add an attribute with always numeric version number

Fix rpm-software-management#9

For example for Fedora Rawhide that would mean that `distro.version`
will be `"rawhide"` and `distro.version_number` will be e.g. `"41"`.

fedora_distro_aliases/__init__.py

@@ -79,7 +79,9 @@ def from_bodhi_release(cls, release):
         Create a `Distro` object from Bodhi `release`
         """
         keys = ["name", "long_name", "version", "state", "branch", "id_prefix"]
-        return cls({k: getattr(release, k) for k in keys})
+        distro = cls({k: getattr(release, k) for k in keys})
+        distro.version_number = distro.version
+        return distro
 
     @property
     def product(self):

tests/test_fedora_distro_aliases.py

@@ -40,6 +40,7 @@ def test_distro():
     assert distro.namever == "foo-123"
     assert distro.product == "fedora"
     assert distro.product == "fedora"
+    assert distro.version_number == "123"
     assert "nonsense" not in distro
     assert "additional" not in distro