wayland/screencopy: fix bo double free on alloc fail in createDmabuf

gbm_bo_free is already called by the WlDmaBuffer destructor

changelog/next.md

@@ -16,3 +16,4 @@
 - Fixed `Toplevel.unsetRectangle` crashing when calle.
 - Fixed intermittent `FileView` crashes when updating watched files.
 - Fixed `ColorQuantizer` deletion crashing if an operation was live.
+- Fixed crashes when failing to create a `ScreencopyView`.

src/wayland/buffer/dmabuf.cpp

@@ -799,7 +799,6 @@ WlBuffer* LinuxDmabufManager::createDmabuf(
 		if (plane.fd < 0) {
 			qCritical(logDmabuf) << "Failed to get gbm_bo fd for plane" << i << qt_error_string(plane.fd);
 			params.destroy();
-			gbm_bo_destroy(bo);
 			return nullptr;
 		}