3cfefd7 Allow importing MMD without xmd["buildrequires"].

Authored and Committed by jkaluza 4 years ago
    Allow importing MMD without xmd["buildrequires"].
    
    When importing modules for offline local builds from local repositories,
    the XMD section does not have to be set at all - it gets removed during
    the compose and is also MBS specific.
    
    We need to be able to import such MMDs using the `import_mmd` method
    in order to make --offline local builds working.
    
    This commit adds new `check_buildrequires` bool kwarg in `import_mmd`
    method to disable `xmd["buildrequires"]` checks to fix this.