New Breaks dependency field

New Breaks dependency field

Documents the new Breaks field supported by dpkg.  This is Ian Jackson's
patch with minor formatting changes and an added note that Breaks should
not be used until Debian stable supports it.  Recommend Breaks instead
of versioned Conflicts once Debian stable supports it.

Remove the paragraph about suidmanager in dpkg-statoverride entirely
since that package no longer exists even in oldstable.

Closes #379150.

git-archimport-id: rra@debian.org--lenny/debian-policy--devel--3.7--patch-33