Apt cannot have 2 mirrors with the same content in 2 different files.
If a deployer has an apt mirror with uca, the deployer
still need to add a repository, but will also need to define the
filename used, in order to avoid clashes.
This commit makes possible to decide the filename for the repo.
Change-Id: I0302b9aea379b9b1974b4479bf85d45d1a052f65