bundler: Handle deprecated license metadata
    
    Adds support for archaic forms of the license metadata in
    package.json where the license field is an object rather than a
    string.
    
    Also removes the need to post-process the 'null' entries.
    
    Resolves: rhbz#1920206
    
    Signed-off-by: Stephen Gallagher <sgallagh@redhat.com>