Text box and rectangle have the same kind and number of handles in
'Edit Point' mode. Only that a text box has an additional handle for
its blinking frame. The error was, that this special one was not
skipped for a rectangle.

Change-Id: Iae7af3eb196e61e32ecd5a39ba0ec553bbdaaa48
Reviewed-on: https://gerrit.libreoffice.org/63070
Tested-by: Jenkins
Reviewed-by: Regina Henschel <rb.henschel@t-online.de>