by using for-range loops
+ use empty() instead of comparing begin and end iterator

Change-Id: I41c3ae0c9032d6349afb113d457cb78862ae9dcf
Reviewed-on: https://gerrit.libreoffice.org/49416Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>