release: remove metrics from unstable channel (temporarily)
release: remove metrics from unstable channel (temporarily)

Since friday the metrics machine (along with other replaceable ones)
has no public-IP connectivity.  I hoped I'd be able to resolve this
with ISP quickly, but apparently not.  Let's not block the channel
at least.  The metrics data can get filled retrospectively by restarting
the individual Hydra jobs.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs