redo mkinitrd.sh to not use volumes

Signed-off-by: Justin Cormack <justin.cormack@unikernel.com>

alpine/Dockerfile

@@ -8,6 +8,8 @@ RUN apk update && apk upgrade && apk add e2fsprogs docker chrony
 
 COPY etc /etc/
 
+COPY mkinitrd.sh /bin/
+
 RUN \
   setup-timezone -z UTC && \
   rc-update add swap boot && \

alpine/Makefile

@@ -7,7 +7,7 @@ ETCFILES+=etc/init.d/chronyd
 initrd.img: Dockerfile mkinitrd.sh repositories $(ETCFILES)
 	rm -f initrd.img
 	docker build -t moby:test .
-	docker run -i -v $(PWD):/export moby:test /export/mkinitrd.sh
+	docker run -i moby:test /bin/mkinitrd.sh > $@
 
 clean:
 	rm -f initrd.img

alpine/mkinitrd.sh

@@ -48,5 +48,7 @@ mv hosts- hosts
 mv resolv.conf- resolv.conf
 mv hostname- hostname
 
+rm /tmp/bin/mkinitrd.sh
+
 cd /tmp
-find . | cpio -H newc -o > /export/initrd.img
+find . | cpio -H newc -o