title: Cabal: File in tar archive is not in the expected directory
body: <p>I have been unable to install any packages using Cabal, getting an error saying that the tar archive is not in the expected directory.  For example, if I try to do, <code>cabal install mtl</code>, I get the following error:</p>
  
  <blockquote>
    <p>Resolving dependencies...
    Failed to install text-1.2.1.1
    cabal: Error: some packages failed to install:
    text-1.2.1.1 failed while unpacking the package. The exception was:
    user error (File in tar archive is not in the expected directory. Expected:
    "." but got the following hierarchy: ["text-1.2.1.1"])</p>
  </blockquote>
  
  <p>I have run <code>cabal update</code>, and <code>cabal --version</code> gives the following:</p>
  
  <pre><code>$ cabal --version
  cabal-install version 1.22.5.0 
  using version 1.22.4.0 of the Cabal library 
  </code></pre>
  
  <p>Anyone have any ideas as to why this might be happening?  Let me know if you need any additional information.</p>