fw: use RetxSuppressionExponential in best-route

Retransmission suppression algorithm of best route strategy
is changed from fixed interval to exponential backoff.
This is a semantical change which requires an increment of the
strategy's version number from 2 to 3.
Version 2 is not retained because it's mostly same as version 3.

refs #1913

Change-Id: I0f18511a3b96384b071024864e638ae3b3ec7080
diff --git a/daemon/fw/best-route-strategy2.cpp b/daemon/fw/best-route-strategy2.cpp
index d243a37..2ec786c 100644
--- a/daemon/fw/best-route-strategy2.cpp
+++ b/daemon/fw/best-route-strategy2.cpp
@@ -31,7 +31,7 @@
 
 NFD_LOG_INIT("BestRouteStrategy2");
 
-const Name BestRouteStrategy2::STRATEGY_NAME("ndn:/localhost/nfd/strategy/best-route/%FD%02");
+const Name BestRouteStrategy2::STRATEGY_NAME("ndn:/localhost/nfd/strategy/best-route/%FD%03");
 NFD_REGISTER_STRATEGY(BestRouteStrategy2);
 
 BestRouteStrategy2::BestRouteStrategy2(Forwarder& forwarder, const Name& name)