Add init process for zombie fighting

This adds a small C binary for fighting zombies.  It is mounted under
`/dev/init` and is prepended to the args specified by the user.  You
enable it via a daemon flag, `dockerd --init`, as it is disable by
default for backwards compat.

You can also override the daemon option or specify this on a per
container basis with `docker run --init=true|false`.

You can test this by running a process like this as the pid 1 in a
container and see the extra zombie that appears in the container as it
is running.

```c

int main(int argc, char ** argv) {
	pid_t pid = fork();
	if (pid == 0) {
		pid = fork();
		if (pid == 0) {
			exit(0);
		}
		sleep(3);
		exit(0);
	}
	printf("got pid %d and exited\n", pid);
	sleep(20);
}
```

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/hack/make/binary-daemon b/hack/make/binary-daemon
index e75c44c587..7ce47a2047 100644
--- a/hack/make/binary-daemon
+++ b/hack/make/binary-daemon
@@ -12,5 +12,5 @@ set -e
 	export BINARY_SHORT_NAME="$DOCKER_PROXY_BINARY_NAME"
 	export SOURCE_PATH='./vendor/src/github.com/docker/libnetwork/cmd/proxy'
 	source "${MAKEDIR}/.binary"
-	copy_containerd "$DEST" 'hash'
+	copy_binaries "$DEST" 'hash'
 )