debian: remove old leftovers from config file handling

debian: remove old leftovers from config file handling

ae40dca3211ec35ca235a8a1f34c37e13093ff0d removed the call to the
debian/ucf-remove-fixup script from debian/rules. However the comment
explaining why this call was there was not removed. Additionally the
override_dh_ucf now only calls dh_ucf without doing anything else.

This commit removes the now unused debian/ucf-remove-fixup script, the
leftover comment referring to it and the dh_ucf override which doesn't
do anything but a call of dh_ucf.

Signed-off-by: Maximilian Engelhardt <maxi@daemonizer.de>