Pull request 2617 (don't require global package database)

A few months ago I noticed that pull request 2617[1] implements a change I'd love to see in Cabal: not requiring a global package database for GHCs that support this (7.6 and on). The change is small and self-contained, and looks like a good one to me, but it hasn't been merged. Any chance someone with a commit bit could review? [1] https://github.com/haskell/cabal/pull/2617