Use the repo name in the response for fetch url.

The repository name of the pull request head doesn't necessarily match
the name of the project's repository. This can happen when a user forks
a project but already has a repository of the same name. Use the name
returned in the api response for the fetch url to avoid this edge case.

features/merge.feature

@@ -11,7 +11,7 @@ Feature: hub merge
       get('/repos/defunkt/hub/pulls/164') { json \
         :head => {
           :label => 'jfirebaugh:hub_merge',
-          :repo  => {:private => false}
+          :repo  => {:private => false, :name=>"hub"}
         },
         :title => "Add `hub merge` command"
       }
@@ -34,7 +34,7 @@ Feature: hub merge
       get('/repos/defunkt/hub/pulls/164') { json \
         :head => {
           :label => 'jfirebaugh:hub_merge',
-          :repo  => {:private => false}
+          :repo  => {:private => false, :name=>"hub"}
         },
         :title => "Add `hub merge` command"
       }
@@ -55,7 +55,7 @@ Feature: hub merge
       get('/repos/defunkt/hub/pulls/164') { json \
         :head => {
           :label => 'jfirebaugh:hub_merge',
-          :repo  => {:private => true}
+          :repo  => {:private => true, :name=>"hub"}
         },
         :title => "Add `hub merge` command"
       }
@@ -82,6 +82,21 @@ Feature: hub merge
       Error: jfirebaugh's fork is not available anymore\n
       """
 
+  Scenario: Renamed repo
+    Given the GitHub API server:
+      """
+      require 'json'
+      get('/repos/defunkt/hub/pulls/164') { json \
+        :head => {
+          :label => 'jfirebaugh:hub_merge',
+          :repo  => {:private => false, :name=>"hub-1"}
+        }
+      }
+      """
+    And there is a commit named "jfirebaugh/hub_merge"
+    When I successfully run `hub merge https://github.com/defunkt/hub/pull/164`
+    Then "git fetch git://github.com/jfirebaugh/hub-1.git +refs/heads/hub_merge:refs/remotes/jfirebaugh/hub_merge" should be run
+
   Scenario: Unchanged merge
     When I run `hub merge master`
     Then "git merge master" should be run

lib/hub/commands.rb

@@ -443,8 +443,9 @@ module Hub
         user, branch = pull_data['head']['label'].split(':', 2)
         abort "Error: #{user}'s fork is not available anymore" unless pull_data['head']['repo']
 
-        url = github_project(url.project_name, user).git_url(:private => pull_data['head']['repo']['private'],
-                                                             :https => https_protocol?)
+        repo_name = pull_data['head']['repo']['name']
+        url = github_project(repo_name, user).git_url(:private => pull_data['head']['repo']['private'],
+                                                      :https => https_protocol?)
 
         merge_head = "#{user}/#{branch}"
         args.before ['fetch', url, "+refs/heads/#{branch}:refs/remotes/#{merge_head}"]