storage: use race-free AddNames instead of SetNames
storage: use race-free AddNames instead of SetNames

Commits from parallel builds using `SetNames` removes `names` from
storage for other builds.

Use race-free atomic `AddNames` to prevent breaking of parallel builds.

Signed-off-by: Aditya R <4f9683854fe0b71db89677d592545c6b565c2266@redhat.com>

containers/image,containers/image