[Pkg-emacsen-addons] Bug#884621: yasnippet upgrade problem (0.9 → 0.11/0.12) - Error while loading 50yasnippet

[H.-Dirk Schmitt]

Package: yasnippet
Version: 0.11.0-2 and 0.12.2-1 

On creating a no-change backport package 
(→ ppa:dirk-computer42/c42-backport)
i found the following transistion problem.

yasnippet 0.9 contains the file /etc/emacs/site-start.d/50yasnippet.el

On upgrade this isn't removed until the now transitional package
yasnippet is purged.

So after `apt-get dist-upgrade` it is still existing and lead to the
following error message:
> Error while loading 50yasnippet: Symbol's function definition is
void: yas--initialize


My advice is to ensure explicit removal of this outdated file.