osxvideo: use avfoundation indev

Remove avfgrab and avfcapture patches, as their functionality is already
in FFmpeg with avfoundation.

Reduces the amount of code to maintain.

Change-Id: I6413821ad6d969dacf651c0fb7516c2499e89e07
Reviewed-by: Anthony LĂ©onard <anthony.leonard@savoirfairelinux.com>
diff --git a/src/media/video/osxvideo/video_device_impl.mm b/src/media/video/osxvideo/video_device_impl.mm
index 3d66a7d..5fc7774 100644
--- a/src/media/video/osxvideo/video_device_impl.mm
+++ b/src/media/video/osxvideo/video_device_impl.mm
@@ -97,7 +97,7 @@
     DeviceParams params;
     params.name = [[avDevice_ localizedName] UTF8String];
     params.input = device;
-    params.format = "avfcapture";
+    params.format = "avfoundation";
 
     params.width = current_size_.first;
     params.height = current_size_.second;