update ms2

diff --git a/mediastreamer2 b/mediastreamer2
index 674c20e4f186a8c2a3f91294aaa7b4bf419b7c3d..a8538b58b7845f06f8526aca9bcf6657cf0abea5 160000 (submodule)
--- a/mediastreamer2
+++ b/mediastreamer2
@@ -1 +1 @@
-Subproject commit 674c20e4f186a8c2a3f91294aaa7b4bf419b7c3d
+Subproject commit a8538b58b7845f06f8526aca9bcf6657cf0abea5