No longer ship /etc/skel/.kshrc [Closes: issue2160]

The ksh package also ships the file /etc/skel/.kshrc and
therefore package installation of grml-etc together with ksh
files.

We didn't have any real changes in our file for more than
10 years. If someone is interested in getting a proper
kshrc within Grml/grml-etc we can re-evaluate our options
before getting in the dark™ with dpkg-diverting another
configuration file.