Some builders return absolute paths to build products already. When that
happens, the manifest writing logic shouldn't tack on another absolute
prefix.
Signed-off-by: David Anderson <danderson@tailscale.com>
By default, cmd/dist only prints the output of failed commands.
With this, you can turn all the noisy output back on.
Updates tailscale/corp#9045
Signed-off-by: David Anderson <danderson@tailscale.com>
