Update helper.rb

fix_device_mapping should return nil where fixed_device does not match /dev/xvd. This should fix creating ephemeral for m2.2xlarge.
Update ephemeral_lvm_helper_spec.rb

Update the test case to make sure Chef:Log return is not added to the list of devices.
Update ephemeral_lvm_helper_spec.rb

Chef:Log:warn returns array, make sure that array is not part of device list.
Merge pull request #13 from autrejacoupa/patch-1

fix_device_mapping should return nil where fixed_device does not match /dev/xvd. This should fix creating ephemeral for m2.2xlarge.