fw: pass const shared_ptr<pit::Entry>& to Strategy triggers

refs #3205

Change-Id: I8f227c57ee6733526f0569de81f20677210cafa4
diff --git a/daemon/fw/multicast-strategy.cpp b/daemon/fw/multicast-strategy.cpp
index 5373d03..44c8c52 100644
--- a/daemon/fw/multicast-strategy.cpp
+++ b/daemon/fw/multicast-strategy.cpp
@@ -38,9 +38,8 @@
 }
 
 void
-MulticastStrategy::afterReceiveInterest(const Face& inFace,
-                                        const Interest& interest,
-                                        shared_ptr<pit::Entry> pitEntry)
+MulticastStrategy::afterReceiveInterest(const Face& inFace, const Interest& interest,
+                                        const shared_ptr<pit::Entry>& pitEntry)
 {
   const fib::Entry& fibEntry = this->lookupFib(*pitEntry);
   const fib::NextHopList& nexthops = fibEntry.getNextHops();