The package is in need of an update because it does not adhere to
the guidelines for packaging static libraries:

  http://fedoraproject.org/wiki/Packaging:Guidelines#Packaging_Static_Libraries

The -devel package contains both the shared and the static build of
a library. That makes it possible to link statically with the -devel
package as a build requirement instead of having to build-require a
special-purpose -static subpackage.

Correct would be to either disable/delete the static libraries at
build-time, or to %exclude them in the %files section, or to split off
a -static subpackage (if there is a compelling reason as why the static
libs should be made available).

Please consult the guidelines for the details.

[...]

xen-devel
    /usr/lib/libblktap.so  <=>  /usr/lib/libblktap.a
    /usr/lib/libflask.so  <=>  /usr/lib/libflask.a
    /usr/lib/libxenctrl.so  <=>  /usr/lib/libxenctrl.a
    /usr/lib/libxenguest.so  <=>  /usr/lib/libxenguest.a
    /usr/lib/libxenstore.so  <=>  /usr/lib/libxenstore.a