Fix - keep stat painter even when object is not there

Server-side histogram may not have TPaveStats object,
which is shown on client side. Therefore not remove statpainter when
doing histogram update.

Author: linev

scripts/JSRootPainter.hist.js

@@ -2225,15 +2225,12 @@
          // The only that could be done is update of content
 
          // check only stats bit, later other settings can be monitored
+         var statpainter = this.FindPainterFor(this.FindStat());
          if (histo.TestBit(JSROOT.TH1StatusBits.kNoStats) != obj.TestBit(JSROOT.TH1StatusBits.kNoStats)) {
             histo.fBits = obj.fBits;
-
-            var statpainter = this.FindPainterFor(this.FindStat());
             if (statpainter) statpainter.Enabled = !histo.TestBit(JSROOT.TH1StatusBits.kNoStats);
          }
 
-         // if (histo.TestBit(JSROOT.TH1StatusBits.kNoStats)) this.ToggleStat();
-
          // special treatment for webcanvas - also name can be changed
          if (this.snapid !== undefined)
             histo.fName = obj.fName;
@@ -2349,6 +2346,11 @@
                   }
                }
 
+            if (statpainter) {
+               var indx = painters.indexOf(statpainter);
+               if (indx >= 0) painters.splice(indx, 1);
+            }
+
             // remove all function which are not found in new list of primitives
             if (pp && (painters.length > 0))
                pp.CleanPrimitives(function(p) { return painters.indexOf(p) >= 0; });