[chronojump] Fixed a crash at encoder capture on last commit

[Xavier de Blas <xaviblas src gnome org>]

commit 3c7e7175387e40a9280010cae4ab3207911b303e
Author: Xavier de Blas <xaviblas gmail com>
Date:   Mon Apr 4 18:02:34 2022 +0200

    Fixed a crash at encoder capture on last commit

 src/gui/eventExecute.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/gui/eventExecute.cs b/src/gui/eventExecute.cs
index 2f9723c8a..9267a7cc9 100644
--- a/src/gui/eventExecute.cs
+++ b/src/gui/eventExecute.cs
@@ -3460,12 +3460,12 @@ public class CairoPaintBarplotPreEncoder : CairoPaintBarsPre
 
        protected override bool storeCreated ()
        {
-               return (pegbe.data9Variables.Count > 0);
+               return (pegbe != null && pegbe.data9Variables.Count > 0);
        }
 
        protected override bool haveDataToPlot()
        {
-               return (pegbe.data9Variables.Count > 0);
+               return (pegbe != null && pegbe.data9Variables.Count > 0);
        }
 
        protected override void paintSpecific()