tools/libxl: remove XEN_RUN_DIR from install target

tools/libxl: remove XEN_RUN_DIR from install target

xencommons creates the _hardcoded_ /var/run/xen already, there is no
need to create and package this directory during make install|rpmball.

Without this change installing the resulting xen.rpm will fail on
systems where /var/run is a symlink. rpm complains that '/var/run' (the
symlink) is already owned by some other system rpm package.

Using XEN_RUN_DIR instead of /var/run/xen tree-wide may be done in a
followup patch.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>