vfs: Make '/dev' directory at image creation time

Move runtime creation of '/dev' to image creation to avoid bogus "unable
to create /dev directory" error messages during boot.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

fs/vfs/main.cc

@@ -1558,9 +1558,6 @@ extern "C" void mount_zfs_rootfs(void)
 	if (ret)
 		kprintf("failed to pivot root, error = %s\n", strerror(ret));
 
-	if (mkdir("/dev", 0755) < 0)
-		kprintf("failed to create /dev, error = %s\n", strerror(errno));
-
 	ret = sys_mount("", "/dev", "devfs", 0, NULL);
 	if (ret)
 		kprintf("failed to mount devfs, error = %s\n", strerror(ret));

usr.manifest.skel

@@ -154,3 +154,4 @@
 /tools/lsroute.so: ./tools/route/lsroute.so
 /&/etc/hosts: ../../static/&
 /&/etc/inputrc: ../../static/&
+/&/dev/.keep: ../../static/&