fix two factor authentication when creating a new token

Enable to create a new OAuth token even when user enabled two factor
authentication.

References #399

features/authentication.feature

@@ -98,7 +98,45 @@ Feature: OAuth authentication
     And the exit status should be 1
     And the file "../home/.config/hub" should not exist
 
-  Scenario: Two-factor authentication
+  Scenario: Two-factor authentication, create authorization
+    Given the GitHub API server:
+      """
+      require 'rack/auth/basic'
+      get('/authorizations') {
+        auth = Rack::Auth::Basic::Request.new(env)
+        halt 401 unless auth.credentials == %w[mislav kitty]
+        if request.env['HTTP_X_GITHUB_OTP'] != "112233"
+          response.headers['X-GitHub-OTP'] = "required;application"
+          halt 401
+        end
+        json [ ]
+      }
+      post('/authorizations') {
+        auth = Rack::Auth::Basic::Request.new(env)
+        halt 401 unless auth.credentials == %w[mislav kitty]
+        if request.env['HTTP_X_GITHUB_OTP'] != "112233"
+          response.headers['X-GitHub-OTP'] = "required;application"
+          halt 401
+        end
+        json :token => 'OTOKEN'
+      }
+      get('/user') {
+        json :login => 'mislav'
+      }
+      post('/user/repos') {
+        json :full_name => 'mislav/dotfiles'
+      }
+      """
+    When I run `hub create` interactively
+    When I type "mislav"
+    And I type "kitty"
+    And I type "112233"
+    Then the output should contain "github.com password for mislav (never stored):"
+    Then the output should contain "two-factor authentication code:"
+    And the exit status should be 0
+    And the file "../home/.config/hub" should contain "oauth_token: OTOKEN"
+
+  Scenario: Two-factor authentication, re-use existing authorization
     Given the GitHub API server:
       """
       require 'rack/auth/basic'

lib/hub/github_api.rb

@@ -284,7 +284,9 @@ def obtain_oauth_token host, user, two_factor_code = nil
         else
           # create a new authorization
           res = post "https://#{user}@#{host}/authorizations",
-            :scopes => %w[repo], :note => 'hub', :note_url => oauth_app_url
+            :scopes => %w[repo], :note => 'hub', :note_url => oauth_app_url do |req|
+              req['X-GitHub-OTP'] = two_factor_code if two_factor_code
+            end
           res.error! unless res.success?
           res.data['token']
         end