Better logging of stalling

src/main.cpp

@@ -4468,8 +4468,10 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
                 LogPrint("net", "Requesting block %s peer=%d\n", pindex->GetBlockHash().ToString(), pto->id);
             }
             if (state.nBlocksInFlight == 0 && staller != -1) {
-                if (State(staller)->nStallingSince == 0)
+                if (State(staller)->nStallingSince == 0) {
                     State(staller)->nStallingSince = nNow;
+                    LogPrint("net", "Stall started peer=%d\n", staller);
+                }
             }
         }