Use a bool for ForceDefaults instead of an int

The actual function takes a bool.

While we are doing this, add a couple missing ForceDefaults.

Change-Id: I7fd41c048dae340ca4f339230ceb033349db0faf
diff --git a/aos/events/event_loop.cc b/aos/events/event_loop.cc
index b50162b..2ffad3b 100644
--- a/aos/events/event_loop.cc
+++ b/aos/events/event_loop.cc
@@ -209,7 +209,7 @@
 
   // Now, build up a report with everything pre-filled out.
   flatbuffers::FlatBufferBuilder fbb;
-  fbb.ForceDefaults(1);
+  fbb.ForceDefaults(true);
 
   // Pre-fill in the defaults for timers.
   std::vector<flatbuffers::Offset<timing::Timer>> timer_offsets;