Fix database tasks in test namespace.

[Juanmcuello]

Commit 15fb430 introduced some issues.

Previously to that commit, when I executed rake db:test:clone_structure
the structure was dumped (to structure.sql) and then loaded again no matter whether
the config.active_record.schema_format was set to :sql or :ruby. That was OK
because I'm explicitly saying that I want the structure to be cloned.

Now, when I call the same task, although the structure is dumped, the loaded schema
depends on the value of the config.active_record.schema_format. So If I have it set
to :ruby and then I call rake db:test:clone_structure the loaded file is schema.rb and
not the structure.sql how it is supposed to be according to the name of the task and
its description.

The same thing happens when I call rake db:test:clone. When called,
a new schema.rb is created but the file used to load the schema depends on
config.active_record.schema_format. If I have it set to :sql, a new schema.rb
is created but the structure.sql file is used to create the database. So it is
not consistent.

This pull request solves the problem. When db:test:clone_structure is invoked, the
structure is dumped and then loaded into the test database. When db:test:clone is
invoked the schema is dumped and then loaded into the test database. None of these
tasks depends now on the value of config.active_record.schema_format

[josevalim]

Reverting because it broke the build:

http://travis-ci.org/#!/rails/rails/jobs/424116

[Juanmcuello]

Sorry, because the changes were in activerecord I just only run those tests, I should have run the whole test suit instead.

I fixed the problem and now tests pass. Should I create a new pull request?

[josevalim]

please new pull request :)