add missing changelog entry for PR #1967
mention issue
Merge pull request #1970 from r1chardj0n3s/insecure-localhost-exception-changelog

add missing changelog entry for PR #1967
Add changelog for --no-check-certificate #1741
Alter the use of the Link objects in PackageFinder to store the version and package name, and
remove the use of the (version, link, version) tuple.

Also fixes bug I noticed in pip/commands/list.py where an uninitialised variable could have
been used.