Bitcoin-Qt: never display own block count > estimated block count

- some users reported it as weird, that the estimated block count could be
  lower than our own nodes block number (which is indeed true and not good)
- this pull adds a new default behaviour, which displays our own block
  number as estimated block number, if own >= est. block count
- the pull raises space for nodes block counts in cPeerBlockCounts to 8 to
  be more accurate
- also removes a reduntant setNumBlocks() call in RPCConsole and moves
  initialisation of numBlocksAtStartup in ClientModel, where it belongs

src/qt/clientmodel.cpp

@@ -15,10 +15,8 @@ static const int64 nClientStartupTime = GetTime();
 
 ClientModel::ClientModel(OptionsModel *optionsModel, QObject *parent) :
     QObject(parent), optionsModel(optionsModel),
-    cachedNumBlocks(0), cachedNumBlocksOfPeers(0), pollTimer(0)
+    cachedNumBlocks(0), cachedNumBlocksOfPeers(0), numBlocksAtStartup(-1), pollTimer(0)
 {
-    numBlocksAtStartup = -1;
-
     pollTimer = new QTimer(this);
     pollTimer->setInterval(MODEL_UPDATE_DELAY);
     pollTimer->start();
@@ -65,7 +63,8 @@ void ClientModel::updateTimer()
         cachedNumBlocks = newNumBlocks;
         cachedNumBlocksOfPeers = newNumBlocksOfPeers;
 
-        emit numBlocksChanged(newNumBlocks, newNumBlocksOfPeers);
+        // ensure we return the maximum of newNumBlocksOfPeers and newNumBlocks to not create weird displays in the GUI
+        emit numBlocksChanged(newNumBlocks, std::max(newNumBlocksOfPeers, newNumBlocks));
     }
 }