packaging: remove the explicit requires on kmod-libs
    
    The main kmod package requires kmod-libs, via the "Requires:
    %{name}-libs%{?_isa} = %{version}-%{release}" line in
    kmod.spec. This is not actually necessary: /bin/kmod statically
    links to libkmod (which is all that's in kmod-libs), and besides,
    if it was dynamically linked rpm would generate the dependency
    automatically.
    
    kmod-devel, on the other hand, should require kmod-libs instead
    of the main kmod package.
    
    (credits for the text to David Shea)
    
    Resolves: rhbz#1208554.
    
    Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>