ZendClient breaks when receiving a HTTP/2 response (#867)

Ref magento/zf1#23

```
The issue is caused by the fact that the response result is checked by a regular expression that expects the Protocol version in the d.d format (for example, 1.0 or 1.1). For HTTP 2.0, the header returns a value in the format "HTTP/2 200 OK" without the decimal part. This results in an error.
```

lib/Zend/Http/Response.php

@@ -182,7 +182,7 @@ public function __construct($code, array $headers, $body = null, $version = '1.1
         $this->body = $body;
 
         // Set the HTTP version
-        if (! preg_match('|^\d\.\d$|', $version)) {
+        if (! preg_match('|^\d+(?:\.\d+)?$|', $version)) {
             #require_once 'Zend/Http/Exception.php';
             throw new Zend_Http_Exception("Invalid HTTP response version: $version");
         }
@@ -514,7 +514,7 @@ public static function extractHeaders($response_str)
         $last_header = null;
 
         foreach($lines as $index => $line) {
-            if ($index === 0 && preg_match('#^HTTP/\d+(?:\.\d+) [1-5]\d+#', $line)) {
+            if ($index === 0 && preg_match('#^HTTP/\d+(?:\.\d+)? [1-5]\d+#', $line)) {
                 // Status line; ignore
                 continue;
             }