Fix #1210927 - Fix undo for the Freeform Shape tool.
Fix #1210927 - Fix undo for the Freeform Shape tool.

The history item was being created before the final draw occurred, so
the surface diff didn't have any changes.

PintaProject/Pinta,jakeclawson/Pinta,jakeclawson/Pinta,Mailaender/Pinta,Fenex/Pinta,Fenex/Pinta,Mailaender/Pinta,PintaProject/Pinta,PintaProject/Pinta