tests: Set lockspace and resource names as bytes
    
    This patch is a preparation for next changes in sanlock
    where lockspace and resource names will be parsed as bytes
    in both python versions and also as ascii string in python 2
    for back compatibility.
    
    Implications:
    
    - Py2: no difference, ascii strings and bytes are parsed the same
    - Py3: marked as xfail as currently expecting only unicode string