Make the BattOr agent retry start tracing when we fail to read an ack

tools/battor_agent/battor_agent.h

Index: tools/battor_agent/battor_agent.h
diff --git a/tools/battor_agent/battor_agent.h b/tools/battor_agent/battor_agent.h
index cc3a7c36139e9961e4c5c5ed0a4d69ef47684674..87be4fccfcee206daeb1fe4593b6d7562571f1f6 100644
--- a/tools/battor_agent/battor_agent.h
+++ b/tools/battor_agent/battor_agent.h
@@ -183,6 +183,9 @@ class BattOrAgent : public BattOrConnection::Listener,
   // The number of times we've attempted to init the BattOr.
   uint8_t num_init_attempts_;
 
+  // The number of times we've attempted the BattOr StartTracing command.
+  uint8_t num_start_tracing_attempts_;
+
   // The number of times that we've attempted to read the last message.
   uint8_t num_read_attempts_;