Fix Failing "test_any_should_not_load_results"

As mentioned on this thread and on the comments of this commit, there is a test which breaks if you have an older version of Mocha installed. Here's the message it gives.

  1) Failure:
test_any_should_not_load_results(NamedScopeTest)
    [./test/cases/../../lib/active_record/test_case.rb:40:in `assert_queries'
     ./test/cases/named_scope_test.rb:189:in `test_any_should_not_load_results'
     ./test/cases/../../lib/../../activesupport/lib/active_support/testing/setup_and_teardown.rb:94:in `__send__'
     ./test/cases/../../lib/../../activesupport/lib/active_support/testing/setup_and_teardown.rb:94:in `run']:
0 instead of 1 queries were executed.
<1> expected but was
<0>.

Attached is a patch which fixes this problem by not using Mocha.