Rails3: scm: mercurial: fix error of test_diff at functional test

On Rails 3.1, ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection error raises.
For more details, see r7062.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@7211 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/functional/repositories_mercurial_controller_test.rb

@@ -271,8 +271,10 @@ class RepositoriesMercurialControllerTest < ActionController::TestCase
     end
 
     def test_diff
+      assert_equal 0, @repository.changesets.count
       @repository.fetch_changesets
-      @repository.reload
+      @project.reload
+      assert_equal NUM_REV, @repository.changesets.count
       [4, '4', 'def6d2f1254a'].each do |r1|
         # Full diff of changeset 4
         ['inline', 'sbs'].each do |dt|