Simplify spec file a little bit
    
    The plugin for cifs-utils can be built on all supported versions of fedora.
    Conditions are required only in upstream spec file for older
    distributions. Definition of constant with_cifs_utils_plugin is still
    in the beginning of spec file for simpler comparison of changes
    between upstream and fedora.
    
    (cherry picked from commit 5ce8ae11668688c221b153694bab28f954afa851)
    (cherry picked from commit 601bb9f4ebf147cb21b99165446d72b5efbf270d)