<socket: 8>: hClose: resource vanished (Broken pipe)

I get the following error when I try to install a package using latest cabal:

```
Resolving dependencies...
sibi::sibi-desktop { ~/sandbox-test }-> cabal install --only-dependencies
Downloading attoparsec-0.12.1.0...
Failed to install attoparsec-0.12.1.0
cabal: Error: some packages failed to install:
attoparsec-0.12.1.0 failed while downloading the package. The exception was:
: hClose: resource vanished (Broken pipe)
```

Cabal version used:

```
sibi::sibi-desktop { ~/sandbox-test }-> cabal --version
cabal-install version 1.20.0.2
using version 1.20.0.1 of the Cabal library
```

Additional information: I'm working under proxy. If I switch to older version of cabal (the one shipped with Ubuntu distribution), It installs the package without any problem.

Let me know if you need any additional information.

Start by reproducing `cabal install --only-dependencies` through the reported proxy with cabal-install 1.20.0.2, then compare it with the older Ubuntu-shipped version. The issue is resolved when package downloads succeed through the proxy without the broken-pipe error.

Written by the indexing model from the issue text.