Only log time samples in debug mode

The full list of time samples is rarely useful outside of debugging.
The node's time offset, however is useful for discovering local clock
drift, so it's displayed in all logging modes.

src/util.cpp

@@ -977,9 +977,12 @@ void AddTimeData(unsigned int ip, int64 nTime)
                 }
             }
         }
-        BOOST_FOREACH(int64 n, vTimeOffsets)
-            printf("%+"PRI64d"  ", n);
-        printf("|  nTimeOffset = %+"PRI64d"  (%+"PRI64d" minutes)\n", nTimeOffset, nTimeOffset/60);
+        if (fDebug) {
+            BOOST_FOREACH(int64 n, vTimeOffsets)
+                printf("%+"PRI64d"  ", n);
+            printf("|  ");
+        }
+        printf("nTimeOffset = %+"PRI64d"  (%+"PRI64d" minutes)\n", nTimeOffset, nTimeOffset/60);
     }
 }