Remove obsolete %defattr
    
    The use of %defattr has been unneeded since rpm-4.4.  It was removed
    from the guidelines 6 years ago¹.  It was kept to allow builds on EL-5,
    which has been EOL since March of last year.
    
    ¹ https://pagure.io/packaging-committee/issue/77
      %defattr is no longer needed in Fedora