update ms2 to clean up ffmpeg dependencies

diff --git a/mediastreamer2 b/mediastreamer2
index c18e8a3e87cd1e972829c6a23efea44ecc4a5612..c58afa69d103ee4f58a1d6ef5e5fccbd15288d9c 160000 (submodule)
--- a/mediastreamer2
+++ b/mediastreamer2
@@ -1 +1 @@
-Subproject commit c18e8a3e87cd1e972829c6a23efea44ecc4a5612
+Subproject commit c58afa69d103ee4f58a1d6ef5e5fccbd15288d9c