Don't include initramfs files in initramfs-extra
When testing on pmOS with qemu/x86_64, this results in some nice reduction in size of the initramfs-extra (gzip'd, default compression):
Before:
/mkinitfs # ls -la /boot/initramfs-extra
-rw-r--r-- 1 root root 3544429 Mar 19 23:06 /boot/initramfs-extra
After:
/mkinitfs # ls -la /boot/initramfs-extra
-rw-r--r-- 1 root root 2234020 Mar 19 23:08 /boot/initramfs-extra
Fixes #23 (closed)