fixed xml driver

lib/Gedmo/Translatable/Mapping/Driver/Xml.php

@@ -66,7 +66,7 @@ class Xml extends BaseXml
                     /** @var \SimpleXmlElement $data */
                     $data = $mapping->translatable;
                     if ($this->_isAttributeSet($data, 'fallback')) {
-                        $config['fallback'][$field] = $this->_getAttribute($data, 'fallback');
+                        $config['fallback'][$field] = 'true' == $this->_getAttribute($data, 'fallback') ? true : false;
                     }
                 }
             }

tests/Gedmo/Mapping/Xml/TranslatableMappingTest.php

@@ -67,5 +67,9 @@ class TranslatableMappingTest extends BaseTestCaseOM
         $this->assertCount(4, $config['fields']);
         $this->assertTrue(in_array('title', $config['fields']));
         $this->assertTrue(in_array('content', $config['fields']));
+        $this->assertTrue(in_array('author', $config['fields']));
+        $this->assertTrue(in_array('views', $config['fields']));
+        $this->assertTrue($config['fallback']['author']);
+        $this->assertFalse($config['fallback']['views']);
     }
 }