Fixes failing spec for Page.copy when using postgresql

The original test passes with acts-as-taggable-on v2.4.0. Since v2.4.1 this test is failing with postgresql. (https://github.com/mbleigh/acts-as-taggable-on/issues/363)

Because we dont want to test the ordering of the tags using postgresql this is a workaround to get the test passing again.