(fixtures): Fix cloud module reference (need to be a symlink)

In order to run rspec tests on the current branch/patchset, cloud
module (in fixtures directory) need to be a symlink on the working
directory, otherwise the rspec test use master branch of cloud module.

Refs: #724
Merge pull request #727 from enovance/fixtures-symlink

(fixtures): Fix cloud module reference (need to be a symlink)