Merge pull request #1945 from astaric/work-around-none

ErrorReporting: Escape string representation of value
(cherry picked from commit 3c89ce8)

Author: janezd

Orange/canvas/application/errorreporting.py

@@ -100,7 +100,7 @@ def _reload_text():
             for k, v in data.items():
                 if k.startswith('_'):
                     continue
-                _v, v = v, escape(v)
+                _v, v = v, escape(str(v))
                 if k == F.WIDGET_SCHEME:
                     if not add_scheme:
                         continue