Merge branch 'hotfix/3340' into develop

Forward port zendframework/zendframework#3340

Author: weierophinney

src/Client/Adapter/Socket.php

@@ -283,8 +283,10 @@ public function connect($host, $port = 80, $secure = false)
                 if (!$test || $error) {
                     // Error handling is kind of difficult when it comes to SSL
                     $errorString = '';
-                    while (($sslError = openssl_error_string()) != false) {
-                        $errorString .= "; SSL error: $sslError";
+                    if (extension_loaded('openssl')) {
+                        while (($sslError = openssl_error_string()) != false) {
+                            $errorString .= "; SSL error: $sslError";
+                        }
                     }
                     $this->close();