Increase number of timing report senders.

With all the threads in wpilib, we blew through the number of senders.

We have no logged data, so this is a fine schema breaking change.

Change-Id: I62381faf9e0f96750e68aacca4a139e8af7ac961
diff --git a/aos/events/shm_event_loop.cc b/aos/events/shm_event_loop.cc
index a8a8e01..bd6d37c 100644
--- a/aos/events/shm_event_loop.cc
+++ b/aos/events/shm_event_loop.cc
@@ -42,9 +42,8 @@
   MMapedQueue(const Channel *channel) {
     std::string path = ShmPath(channel);
 
-    // TODO(austin): Pull these out into the config if there is a need.
-    config_.num_watchers = 10;
-    config_.num_senders = 10;
+    config_.num_watchers = channel->num_watchers();
+    config_.num_senders = channel->num_senders();
     config_.queue_size = 2 * channel->frequency();
     config_.message_data_size = channel->max_size();