Currently, on installation or upgrade the openvswitch-switch deb package
will in some circumstances modify a pre-existing
/etc/default/openvswitch-switch configuration file.

This does not play well with modeling and configuration management tools
and may lead to unnecessary restarts of the openvswitch-switch service
after the initial restart done as part of the package upgrade. As
restarting the openvswitch-switch affects the datapath this is
something we should try to avoid.

I also believe the current behaviour to be in conflict with best practices
set out in the config files section of the
[Debian Policy](https://www.debian.org/doc/debian-policy/#s-config-files

).

This commit addresses this by removing the part of the postinst script
that attempts to append missing documentation parts of the template
and leaves the installed defaults file alone when it exists.

Fixes: 0aaa379d99f4 ("Debian packaging: Add several new settings to /etc/default/openflow-switch.")
Signed-off-by: Frode Nordahl <frode.nordahl@gmail.com>
Reported-at: https://github.com/openvswitch/ovs-issues/issues/137


Signed-off-by: Ben Pfaff <blp@ovn.org>