by using for-range loops
+ use returned iterator by erase call

Change-Id: Ia41c9fae190dbad6a25b62a9b15ad51e89dd2906
Reviewed-on: https://gerrit.libreoffice.org/48759Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>