tools: Remove kernel-compile. It's no longer used

projects are still using it, but it's still on hub so no
impact.

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>

tools/kernel-compile/Dockerfile

@@ -1,23 +0,0 @@
-FROM alpine:3.5
-RUN \
-  apk update && apk upgrade && \
-  apk add \
-  build-base \
-  argp-standalone \
-  automake \
-  bash \
-  bc \
-  binutils-dev \
-  curl \
-  git \
-  gmp-dev \
-  installkernel \
-  kmod \
-  libelf-dev \
-  linux-headers \
-  ncurses-dev \
-  sed \
-  squashfs-tools \
-  tar \
-  xz \
-  && true

tools/kernel-compile/Makefile

@@ -1,29 +0,0 @@
-.PHONY: tag push
-
-BASE=alpine:3.5
-IMAGE=kernel-compile
-
-default: push
-
-hash:
-	DOCKER_CONTENT_TRUST=1 docker pull $(BASE)
-	tar cf - Dockerfile | docker build --no-cache -t $(IMAGE):build -
-	docker run --rm $(IMAGE):build sha1sum /lib/apk/db/installed | sed 's/ .*//' > hash
-
-push: hash
-	docker pull linuxkit/$(IMAGE):$(shell cat hash) || \
-		(docker tag $(IMAGE):build linuxkit/$(IMAGE):$(shell cat hash) && \
-		 docker push linuxkit/$(IMAGE):$(shell cat hash))
-	docker rmi $(IMAGE):build
-	rm -f hash
-
-tag: hash
-	docker pull linuxkit/$(IMAGE):$(shell cat hash) || \
-		docker tag $(IMAGE):build linuxkit/$(IMAGE):$(shell cat hash)
-	docker rmi $(IMAGE):build
-	rm -f hash
-
-clean:
-	rm -f hash
-
-.DELETE_ON_ERROR: