[bugfix] QA online: resetting of entries number in the qa histograms is fixed

The merge request enables resetting of the entries number in the cbm::algo::qa::Histogram classes.

algo/qa/Histogram.h

@@ -257,6 +257,7 @@ namespace cbm::algo::qa
     {
       TotalSums::Reset();
       fHistogram.reset();
+      fEntries = 0;
     }
 
     /// \brief Sets name