stopAppendOnly resets aof_rewrite_scheduled

althouh in theory, users can do BGREWRITEAOF even if aof is disabled, i
suppose it is more common that the scheduled flag is set by either
startAppendOnly, of a failed initial AOFRW fork (AOF_WAIT_REWRITE)

src/aof.c

@@ -242,6 +242,7 @@ void stopAppendOnly(void) {
     server.aof_fd = -1;
     server.aof_selected_db = -1;
     server.aof_state = AOF_OFF;
+    server.aof_rewrite_scheduled = 0;
     killAppendOnlyChild();
 }