make add-key never fail and never signal change
make add-key never fail and never signal change

this is clearly not the best solution, but there doesn't seem to be a
way to add keys to a repository that hasn't been backed up yet and
add-key doesn't print anything, regardless if a key was added or was
already there (even if --verbose is given).

costela/ansible-role-obnam,costela/ansible-role-obnam