tools: emerge shadow first

_sys-apps/shadow_ needs to be installed explicity, otherwise all
_acct-user/*_ and _acct-group/*_ packages will fail to install.

lib/tools.sh

@@ -1,10 +1,13 @@
 #!/bin/sh
 
+xargs -r emerge -vnuUj --rebuilt-binaries=y --color=y <<EOF
+sys-apps/shadow
+EOF
+
 xargs -r emerge -vnuUj --rebuilt-binaries=y --color=y <<EOF
 sec-policy/selinux-base
 sys-apps/policycoreutils
 sys-apps/kmod
-sys-apps/shadow
 sys-apps/systemd
 sys-boot/grub
 sys-fs/btrfs-progs