Replace vim modeline with Python specific one to avoid problems with
tabs and spaces, and also make code more pythonic.

Change-Id: Ia0959787ceea740b5c97f500c60ef423fbed0651
Reviewed-on: https://gerrit.libreoffice.org/72375
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>