Merge pull request #7821 from open-sausages/pulls/4.0/update-message

Update reference from $databaseConfig to .env

src/Core/CoreKernel.php

@@ -308,7 +308,7 @@ class CoreKernel implements Kernel
         // Error if installer not available
         if (!file_exists($this->basePath . '/install.php')) {
             throw new HTTPResponse_Exception(
-                'SilverStripe Framework requires a $databaseConfig defined.',
+                'SilverStripe Framework requires a .env configuration file',
                 500
             );
         }