Update Qvitter submodule to latest HEAD

diff --git a/plugins/Qvitter b/plugins/Qvitter
index ef3af7fe8dc13671f75f46b393d509ac40f4a80f..d4123836542d5754ea8c6a226234022c1bce15c3 160000 (submodule)
--- a/plugins/Qvitter
+++ b/plugins/Qvitter
@@ -1 +1 @@
-Subproject commit ef3af7fe8dc13671f75f46b393d509ac40f4a80f
+Subproject commit d4123836542d5754ea8c6a226234022c1bce15c3