qcam: Fix camera reference leak on hot-unplug

If the currently streaming camera is hot-unplugged, a camera reference
was still held by MainWindow::camera_, preventing it to be destructed,
until qcam window is closed. Plug the leak in the hot-unplug handler
itself.

Signed-off-by: Umang Jain <email@uajain.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/qcam/main_window.cpp

@@ -587,6 +587,8 @@ void MainWindow::processHotplug(HotplugEvent *e)
 		/* Check if the currently-streaming camera is removed. */
 		if (camera == camera_.get()) {
 			toggleCapture(false);
+			camera_->release();
+			camera_.reset();
 			cameraCombo_->setCurrentIndex(0);
 		}