fix zip test

tests/Composer/Test/Downloader/ZipDownloaderTest.php

@@ -64,6 +64,10 @@ class ZipDownloaderTest extends \PHPUnit_Framework_TestCase
             ->with('cafile')
             ->will($this->returnValue(null));
         $config->expects($this->at(2))
+            ->method('get')
+            ->with('capath')
+            ->will($this->returnValue(null));
+        $config->expects($this->at(3))
             ->method('get')
             ->with('vendor-dir')
             ->will($this->returnValue($this->testDir));