### Please describe the problem.
[[!format sh """
cabal install -O2 -j1 -f-webdav -f-s3 git-annex
Resolving dependencies...
Configuring dns-1.2.0...
Building dns-1.2.0...
Preprocessing library dns-1.2.0...

Network/DNS/Decode.hs:15:8:
    Could not find module `Data.Conduit.Network'
    It is a member of the hidden package `conduit-extra-1.1.0'.
    Perhaps you need to add `conduit-extra' to the build-depends in your .cabal file.
    Use -v to see a list of the files searched for.
Failed to install dns-1.2.0
cabal: Error: some packages failed to install:
dns-1.2.0 failed during the building phase. The exception was:
ExitFailure 1
git-annex-5.20140402 depends on dns-1.2.0 which failed to install.
"""]]

### What steps will reproduce the problem?

[[!format sh """
cabal update
mkdir -p ~/haskell/git-annex
cd ~/haskell/git-annex
cabal sandbox init
cabal install -O2 -j1 -f-webdav -f-s3 c2hs git-annex
"""]]
### What version of git-annex are you using? On what operating system?

5.20140402, Gentoo Linux

### Please provide any additional information below.

> [[fixed|done]] --[[Joey]]
