Update ms2 (ffmpeg version issue)

[linphone] / mediastreamer2

diff --git a/mediastreamer2 b/mediastreamer2
index c799531d9403c50fb06965a921e1530c814e02a1..1a69168c1f30a7be439606069bd8dc4d5becac02 160000 (submodule)
--- a/mediastreamer2
+++ b/mediastreamer2
@@ -1 +1 @@
-Subproject commit c799531d9403c50fb06965a921e1530c814e02a1
+Subproject commit 1a69168c1f30a7be439606069bd8dc4d5becac02