Changes default timezone to the same as expected on tests

The date formatting as text is based on current timezone. The test failed on
every timezone but Bangalore's.
The exception message changes on different Ruby (and JRuby) versions.

+      # The exception message change depending on ruby version
Don't rely on order, just on content.

The serialization can be different depending (depending on active_suport
version) but the content should always be the same.
Merge pull request #163 from juniorz/tests

Fix tests