Fix lintian-warning: init.d-script-does-not-source-init-functions

The /etc/init.d/uanytun script does not source /lib/lsb/init-functions. The
systemd package provides /lib/lsb/init-functions.d/40-systemd to redirect
/etc/init.d/$script calls to systemctl.

When a init script sources the /lib/lsb/init-functions utility
we have to declare a dependency on lsb-base (>= 3.0-6).

This patch includes an upstream commit which was commited after the release of v0.3.6
Source: https://git.spreadspace.org/anytun/uanytun.git/commit/?id=e84f028444822b2a185395a640c5e12da4db8454