Set the new GitHub import as import source

lib/gitlab/import_sources.rb

@@ -8,7 +8,7 @@ module Gitlab
     ImportSource = Struct.new(:name, :title, :importer)
 
     ImportTable = [
-      ImportSource.new('github',         'GitHub',        Gitlab::GithubImport::Importer),
+      ImportSource.new('github',         'GitHub',        Github::Import),
       ImportSource.new('bitbucket',      'Bitbucket',     Gitlab::BitbucketImport::Importer),
       ImportSource.new('gitlab',         'GitLab.com',    Gitlab::GitlabImport::Importer),
       ImportSource.new('google_code',    'Google Code',   Gitlab::GoogleCodeImport::Importer),

spec/lib/gitlab/import_sources_spec.rb

@@ -56,7 +56,7 @@ describe Gitlab::ImportSources do
 
   describe '.importer' do
     import_sources = {
-      'github' => Gitlab::GithubImport::Importer,
+      'github' => Github::Import,
       'bitbucket' => Gitlab::BitbucketImport::Importer,
       'gitlab' => Gitlab::GitlabImport::Importer,
       'google_code' => Gitlab::GoogleCodeImport::Importer,