[qt] sync-overlay: Don't show progress twice

* Don't show integer progress in progress bar. (Already shown in front
  of progress bar)

* Also, use non-static method to get current msecs

src/qt/forms/modaloverlay.ui

@@ -276,6 +276,9 @@ QLabel { color: rgb(40,40,40);  }</string>
                <property name="value">
                 <number>24</number>
                </property>
+               <property name="format">
+                <string/>
+               </property>
               </widget>
              </item>
             </layout>

src/qt/modaloverlay.cpp

@@ -77,7 +77,7 @@ void ModalOverlay::tipUpdate(int count, const QDateTime& blockDate, double nVeri
     QDateTime currentDate = QDateTime::currentDateTime();
 
     // keep a vector of samples of verification progress at height
-    blockProcessTime.push_front(qMakePair(currentDate.currentMSecsSinceEpoch(), nVerificationProgress));
+    blockProcessTime.push_front(qMakePair(currentDate.toMSecsSinceEpoch(), nVerificationProgress));
 
     // show progress speed if we have more then one sample
     if (blockProcessTime.size() >= 2)
@@ -93,8 +93,7 @@ void ModalOverlay::tipUpdate(int count, const QDateTime& blockDate, double nVeri
             QPair<qint64, double> sample = blockProcessTime[i];
 
             // take first sample after 500 seconds or last available one
-            if (sample.first < (currentDate.currentMSecsSinceEpoch() - 500*1000) || i == blockProcessTime.size()-1)
-            {
+            if (sample.first < (currentDate.toMSecsSinceEpoch() - 500 * 1000) || i == blockProcessTime.size() - 1) {
                 progressDelta = progressStart-sample.second;
                 timeDelta = blockProcessTime[0].first - sample.first;
                 progressPerHour = progressDelta/(double)timeDelta*1000*3600;
@@ -108,7 +107,6 @@ void ModalOverlay::tipUpdate(int count, const QDateTime& blockDate, double nVeri
         // show expected remaining time
         ui->expectedTimeLeft->setText(GUIUtil::formateNiceTimeOffset(remainingMSecs/1000.0));
 
-        // keep maximal 5000 samples
         static const int MAX_SAMPLES = 5000;
         if (blockProcessTime.count() > MAX_SAMPLES)
             blockProcessTime.remove(MAX_SAMPLES, blockProcessTime.count()-MAX_SAMPLES);