Installation fails: recaptcha does not build because Network.URI cannot be found.

Hi, during installation with `cabal install --reinstall gitit` an error is displayed when installating recaptcha:

```
...
Failed to install recaptcha-0.1.0.2
Build log ( /home/neitsab/.cabal/logs/recaptcha-0.1.0.2.log ):
[1 of 1] Compiling Main ( /tmp/recaptcha-0.1.0.2-20176/recaptcha-0.1.0.2/dist/setup/setup.hs, /tmp/recaptcha-0.1.0.2-20176/recaptcha-0.1.0.2/dist/setup/Main.o )
Linking /tmp/recaptcha-0.1.0.2-20176/recaptcha-0.1.0.2/dist/setup/setup ...
Configuring recaptcha-0.1.0.2...
Building recaptcha-0.1.0.2...
Preprocessing library recaptcha-0.1.0.2...

Network/Captcha/ReCaptcha.hs:41:8:
Could not find module ‘Network.URI’
It is a member of the hidden package ‘network-uri-2.6.0.0’.
Perhaps you need to add ‘network-uri’ to the build-depends in your .cabal file.
Use -v to see a list of the files searched for.
...
```

And as a consequence...

```
...
cabal: Error: some packages failed to install:
gitit-0.10.5 depends on recaptcha-0.1.0.2 which failed to install.
recaptcha-0.1.0.2 failed during the building phase. The exception was:
ExitFailure 1
```

I guess this is linked to commit ff6cd2f12023c12bb84843c36ddd4559056dc2d8. I'm on Arch Linux, did `cabal update && cabal install --reinstall -fhighlighting pandoc` prior to this. By the way, why is pandoc rebuilt during gitit installation?

Thanks