spec: Drop the old sysv initscript files
    
    We aren't building for the old SysV initscripts package any more, so
    drop the ifup-ib/ifdown-ib scripts that only work when the initscripts
    package is installed.  This keeps us in line with changes going into the
    rdma-core-17 package release.
    
    Signed-off-by: Doug Ledford <dledford@redhat.com>