Custom name for OmniAuth GitHub import isn't respected

When using OmniAuth or the social connect option, entering a custom name for a GitHub import won't be respected.

new_name isn't sent through on the POST /import/github ajax request.

A custom name in the GitHub import process works just fine if you use a normal account and use either GitHub authorization flow(personal access token or list your GitHub repositories via authorized OAuth application)

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This is not a regression from https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4688. It was present on master before merge (currently the MR isn't even merged).

cc @jramsay