client: check event opcode in queue_event

If the client binds to a global with an interface mismatch, it may receive an
event from the server with an unknown opcode. See [1].

Instead of crashing, print a more useful debug message and close the connection.

[1]: https://gitlab.freedesktop.org/wayland/wayland/issues/113



Signed-off-by: Simon Ser <simon.ser@intel.com>