Don't make "in" parameters look like "out"/"in-out" parameters: pass by ref to const instead of ref to non-const

src/test/addrman_tests.cpp

@@ -71,7 +71,7 @@ public:
     }
 
     // Simulates connection failure so that we can test eviction of offline nodes
-    void SimConnFail(CService& addr)
+    void SimConnFail(const CService& addr)
     {
          LOCK(cs);
          int64_t nLastSuccess = 1;