Fix uPnP context destroy

[linphone] / mediastreamer2

diff --git a/mediastreamer2 b/mediastreamer2
index 4ed2e518cf79c62fe8df7f23ce99e0fbfe2e799d..c48f1a31d850ed9a1b607985d2a250a8ca048547 160000 (submodule)
--- a/mediastreamer2
+++ b/mediastreamer2
@@ -1 +1 @@
-Subproject commit 4ed2e518cf79c62fe8df7f23ce99e0fbfe2e799d
+Subproject commit c48f1a31d850ed9a1b607985d2a250a8ca048547