wayland-info: Fix runtime warning

The dmabuf_feedback was leaked, causing the following runtime warning with recent Wayland libraries:

warning: queue 0x15c8390 destroyed while proxies still attached: zwp_linux_dmabuf_feedback_v1@14 still attached

Make sure to destroy the dmabuf_feedback proxy along with the rest of the dmabuf info.

Signed-off-by: Olivier Fourdan ofourdan@redhat.com Fixes: 240cb739 - wayland-info: Add support for linux_dmabuf version 4