Missing attribute 'original'

I copy pasted the example messages.en.xliff provided. Running it on symfony 2.6 required me the attribute 'original'.
I added ' original="file.ext" ' as attribute for the file tag and it worked. However I am not shure about the proper parameter for this attribute.
bug #4594 Missing attribute 'original' (Marcelsj)

This PR was submitted for the 2.6 branch but it was merged into the 2.3 branch instead (closes #4594).

Discussion
----------

Missing attribute 'original'

I copy pasted the example messages.en.xliff provided. Running it on symfony 2.6 required me the attribute 'original'.
I added ' original="file.ext" ' as attribute for the file tag and it worked. However I am not shure about the proper parameter for this attribute.

Commits
-------

c0ef3e4 Missing attribute 'original'