Remove errant "runtime.GOARCH" from debug message
Remove errant "runtime.GOARCH" from debug message

This debug message already includes a full platform string, so this ends up being something like `linux/arm/v7/amd64` in the end result.

Signed-off-by: Tianon Gravi <4b2b69742da531f1900c4c4748d7a0ecda59626a@gmail.com>

moby/moby,jimjag/docker,Mokolea/docker,mahak/docker,trebonian/docker,moby/moby,jimjag/docker,Ramzec/docker,Mokolea/docker,Ramzec/docker,trebonian/docker,moby/moby,konstruktoid/docker-upstream,moby/moby,jimjag/docker,thaJeztah/docker,Ramzec/docker,mahak/docker,Mokolea/docker,thaJeztah/docker,thaJeztah/docker,trebonian/docker,Mokolea/docker,thaJeztah/docker,konstruktoid/docker-upstream,konstruktoid/docker-upstream,mahak/docker,mahak/docker,jimjag/docker,trebonian/docker,konstruktoid/docker-upstream,Ramzec/docker