Bug#217862: two complaints about dpkg allowing versioned dependency violations on upgrade

["Nikita V. Youshchenko" <yoush@cs.msu.su>]

> I was tempted to merge #217862 and #170825 but I can't be sure
> that they report the same bug since the former involves a
> normal dependency and the latter involves a dependency on a
> virtual package.  However, the submitters of these bugs may
> be interested to compare notes.

Yes, this really seems to be the same problem: dpkg does not check if new 
version of a package still satisfies the dependences that have been 
satisfied by the old varsion of the same package.