Bind callback of history_revisions to the tab form

bd73cefcf802 backported code that uses `this` but the upper versions are using
arrow functions.

Closes #12642

--HG--
branch : 6.0

sao/src/tab.js

@@ -1041,7 +1041,7 @@
                         }
                         new Sao.Window.Revision(
                             revisions, revision, set_revision(revisions));
-                    });
+                    }.bind(this));
             }.bind(this));
         },
         update_revision: function() {