Avoid deadlock on unknown user channel

fix.txt

@@ -37,14 +37,14 @@ Priority 0: security and crashers
    nil. Initialize the map in DialWithDialer and assign its owning client when
    actions are created. Add handler tests for add/remove/trigger.
 
-4. Unknown ChannelId deadlocks the protocol reader
+[x] 4. Unknown ChannelId deadlocks the protocol reader
    File: gumble/gumble/handlers.go
    In handleUserState, the unknown ChannelId branch takes c.volatile.Lock()
    again instead of unlocking before returning. This leaves the mutex locked
    forever. Replace with one unlock (prefer defer after acquisition) and add
    a malformed/out-of-order channel test.
 
-5. OpenAL Buffer.Delete deletes a source, not a buffer
+[x] 5. OpenAL Buffer.Delete deletes a source, not a buffer
    File: gumble/go-openal/openal/buffer.go
    Buffer.Delete calls C.walDeleteSource. It must call C.walDeleteBuffer.
    The current code reports invalid source errors and leaks OpenAL buffers.