[arch-ports] Booting i686 iso in VirtualBox

[Tyler Dence]

So a quick update on where this is.

We've figured out that the issue was caused by an update to the glibc
package in the mainline repos. Pinning this back to a known good version
allowed us to build working -i686.iso and -dual.iso images. These have been
put in the master repo and should be syncing elsewhere shortly.

Let us know if you have any issues with the new archlinux-2017.06.15-*.iso
images.

Thanks,
Tyler