Fix fragile translation test.

The test required an exact string match.  So as the translation API improved, the test broke.

Make the test less fragile by just confirming the Russian word for "world" appears in the output.

Author: SurferJeffAtGoogle

translate/test/quickstartTest.php

@@ -43,6 +43,6 @@ public function testQuickstart()
         $this->assertArrayHasKey('text', $translation);
         $this->assertEquals('en', $translation['source']);
         $this->assertEquals('Hello, world!', $translation['input']);
-        $this->assertEquals('Привет мир!', $translation['text']);
+        $this->assertContains('мир', $translation['text']);
     }
 }