'version' was documented as the intrinsic version (eg. '0.7.2-3') and
'full_version' as the one containing the suite name (eg. 'stretch/contrib/0.7.2-3').
In practice, it was the opposite, except in a few incorrect test.
This commit fixes said tests, and renamed 'full_version' to
'intrinsic_version'.
This is only a refactoring, the behavior is unchanged for now;
but a future commit will remove the 'version' (which is extrinsic) from
the release name (which should contain only data intrinsic to the DSC).
I think it will be better to create a swh.auth.django.models module and put that model in it.
In a similar manner, authentication backends should be put in a swh.auth.django.backends (in an other diff of course).