Upgrade to a version of bmusb with fixed FakeCapture colors.

Found using the new analyzer, actually :-)

diff --git a/bmusb b/bmusb
index b70e557a8432ca3d86c1a71837e7a10e7935d585..838846a92ca196aa8d5c4169d4478d18b9486432 160000 (submodule)
--- a/bmusb
+++ b/bmusb
@@ -1 +1 @@
-Subproject commit b70e557a8432ca3d86c1a71837e7a10e7935d585
+Subproject commit 838846a92ca196aa8d5c4169d4478d18b9486432