kms gpu hotplug fixes

Fix hotplug of GPU after gnome-shell start no longer working (wrong closure function usage).

Fix hot unplug of GPU leading to the monitors attached to that GPU staying around (can still move the cursor offscreen there) and more importantly, fix the first monitor (re)configuration after a GPU hot unplug leading to a crash, from the commit message of the last commit in this merge-req:

Add a listener for the udev device-removed signal and update all monitors / outputs on the device, marking them as disconnected.

As the TODO comment indicates we should probably also remove the GPU itself from our list of GPU objects. But this commit at least gets us to a point where we properly update the list of monitors when a GPU gets unplugged; and where we no longer crash the first time the user changes the monitor configuration after a GPU was unplugged.

Specifically before this commit we would hit the first g_error () in meta_renderer_native_create_view () as soon as some monitor (re)configuration is done after a GPU was unplugged.