fw: rename RetransmissionSuppression to RetxSuppressionFixed

This commit also declares RetxSuppression base class as the API
for any retransmission suppression decision algorithms,
so that other algorithms can be introduced.

refs #1913

Change-Id: I5539565d2dd238d1421f5bd828fde4ecfba0a820
diff --git a/daemon/fw/best-route-strategy2.hpp b/daemon/fw/best-route-strategy2.hpp
index 5a0f3be..603be0e 100644
--- a/daemon/fw/best-route-strategy2.hpp
+++ b/daemon/fw/best-route-strategy2.hpp
@@ -27,7 +27,7 @@
 #define NFD_DAEMON_FW_BEST_ROUTE_STRATEGY2_HPP
 
 #include "strategy.hpp"
-#include "retransmission-suppression.hpp"
+#include "retx-suppression-fixed.hpp"
 
 namespace nfd {
 namespace fw {
@@ -55,7 +55,7 @@
   static const Name STRATEGY_NAME;
 
 private:
-  RetransmissionSuppression m_retransmissionSuppression;
+  RetxSuppressionFixed m_retxSuppression;
 };
 
 } // namespace fw