Ubuntu dropping i386 support

Starting with the upcoming "Eoan Ermine" (a.k.a. 19.10) release, the Ubuntudistribution willnot support 32-bit x86 systems. "The Ubuntu engineering team hasreviewed the facts before us and concluded that we should not continue tocarry i386 forward as an architecture. Consequently, i386 will not beincluded as an architecture for the 19.10 release, and we will shortlybegin the process of disabling it for the eoan series across Ubuntuinfrastructure."