MAGETWO-44733: Installation fails after adding etc/integration/api.xml file to the module

- Fixed Config Reader

Author: Eugene Tulika

app/code/Magento/Integration/Model/Config/Integration/Reader.php

@@ -37,7 +37,7 @@ public function __construct(
         Converter $converter,
         SchemaLocator $schemaLocator,
         \Magento\Framework\Config\ValidationStateInterface $validationState,
-        $fileName = 'integration\api.xml',
+        $fileName = 'integration/api.xml',
         $idAttributes = [],
         $domDocumentClass = 'Magento\Framework\Config\Dom',
         $defaultScope = 'global'