Fix failing spec due to mysql cutting off milliseconds

Spec test was failing on MySQL db due to the way dates are handled.
```
Consumer Resource Content
  should allow content value overrides per consumer (FAILED - 1)

Failures:

  1) Consumer Resource Content should allow content value overrides per consumer
     Failure/Error: results.should =~ returnOverrides
       expected collection contained:  [{"contentLabel"=>"content1.label", "name"=>"field1", "value"=>"3218c5cb-0b08-4d5f-86a8-a5905e184963", "created"=>"2014-03-17T18:03:20.129+0000", "updated"=>"2014-03-17T18:03:20.129+0000"}, {"contentLabel"=>"content2.label", "name"=>"field2", "value"=>"3218c5cb-0b08-4d5f-86a8-a5905e184963", "created"=>"2014-03-17T18:03:20.131+0000", "updated"=>"2014-03-17T18:03:20.131+0000"}]
       actual collection contained:    [{"contentLabel"=>"content1.label", "name"=>"field1", "value"=>"3218c5cb-0b08-4d5f-86a8-a5905e184963", "created"=>"2014-03-17T18:03:20.000+0000", "updated"=>"2014-03-17T18:03:20.000+0000"}, {"contentLabel"=>"content2.label", "name"=>"field2", "value"=>"3218c5cb-0b08-4d5f-86a8-a5905e184963", "created"=>"2014-03-17T18:03:20.000+0000", "updated"=>"2014-03-17T18:03:20.000+0000"}]
       the missing elements were:      [{"contentLabel"=>"content1.label", "name"=>"field1", "value"=>"3218c5cb-0b08-4d5f-86a8-a5905e184963", "created"=>"2014-03-17T18:03:20.129+0000", "updated"=>"2014-03-17T18:03:20.129+0000"}, {"contentLabel"=>"content2.label", "name"=>"field2", "value"=>"3218c5cb-0b08-4d5f-86a8-a5905e184963", "created"=>"2014-03-17T18:03:20.131+0000", "updated"=>"2014-03-17T18:03:20.131+0000"}]
       the extra elements were:        [{"contentLabel"=>"content1.label", "name"=>"field1", "value"=>"3218c5cb-0b08-4d5f-86a8-a5905e184963", "created"=>"2014-03-17T18:03:20.000+0000", "updated"=>"2014-03-17T18:03:20.000+0000"}, {"contentLabel"=>"content2.label", "name"=>"field2", "value"=>"3218c5cb-0b08-4d5f-86a8-a5905e184963", "created"=>"2014-03-17T18:03:20.000+0000", "updated"=>"2014-03-17T18:03:20.000+0000"}]
     # ./spec/consumer_resource_content_spec.rb:28:in `block (2 levels) in <top (required)>'
```