Fix for paths with colons

Paths containing a colon (:) are treated as an URI even if they are not, e.g. the following does not work in Guzzle:
<pre><code>$client = new Guzzle\Http\Client('http://en.wikipedia.org/wiki/');
$response = $client->get('Talk:PHP')->send();</code></pre>

This modification fixes the behavior.