Fix Fogbugz Importer not working
This stopped working in GitLab 11.11 when we upgraded to Rails 5.1.  Rails
5.1 changed ActionController::Parameters to return an Object instead of a
Hash (https://eileencodes.com/posts/actioncontroller-parameters-now-returns-an-object-instead-of-a-hash/). The old behavior was deprecated in Rails 5 but finally removed in Rails 5.1.
Since the controller wasn't updated properly, the callback endpoint quietly failed with the message, "Could not connect to FogBugz, check your url".
To fix this, we need to call to_h on the import_params to access
the Hash. We also need to do this for the user map and permit specific keys.
Edited  by Stan Hu