make the cs-bundle optional, for non-composer installations

Author: oscarotero

src/Http/CurlDispatcher.php

@@ -91,7 +91,11 @@ public function dispatch(Url $url)
         }
 
         //Other sites needs a certificate
-        if ($response->getStatusCode() === 0 && strpos($response->getError(), 'SSL') !== false) {
+        if (
+            class_exists('Composer\\CaBundle\\CaBundle')
+         && $response->getStatusCode() === 0 
+         && strpos($response->getError(), 'SSL') !== false
+        ) {
             $options[CURLOPT_SSL_VERIFYHOST] = 2;
             $options[CURLOPT_SSL_VERIFYPEER] = true;
             $options[CURLOPT_CAINFO] = CaBundle::getSystemCaRootBundlePath();