Bug#779905: usr-share-doc-symlink-without-dependency check too weak

[Helmut Grohne <helmut@subdivi.de>]

Package: lintian
Version: 2.5.30+deb8u3

The usr-share-doc-symlink-without-dependency currently misses many
instaces of this problem that are occuring for real in Debian in a
reproducible way causing /usr/share/doc/$pkg/copyright to be out of
sync.

Relevant policy item:
https://www.debian.org/doc/debian-policy/footnotes.html#f116

Examples:
  gcc -> cpp
  debconf-utils (#779420)
  libvlc5 -> libvlccore (#779251)
  libhogweed2 -> libnettle4 (fixed)
  exim4 -> exim4-base (fixed)

In all of these cases there is/was a (>= ...) dependency but no (<< ...)
dependency and in all of these cases you could upgrade the right package
without the left causing the copyright of the left package to be out of
sync.

nettle was fixed with (= ...), exim4 was fixed with (<< ...).

Helmut