Remove unused variables in the code
    
    This commit removes unused variables or rename variables as "expected to
    be unused" by using "_" prefix.
    
    This covers only cases where fix was easy or only one unused variable
    was in a module
    
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>
    Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>