Streams: fix memory leak in freeStream().

src/t_stream.c

@@ -54,6 +54,7 @@ stream *streamNew(void) {
 /* Free a stream, including the listpacks stored inside the radix tree. */
 void freeStream(stream *s) {
     raxFreeWithCallback(s->rax,(void(*)(void*))lpFree);
+    zfree(s);
 }
 
 /* Generate the next stream item ID given the previous one. If the current