[Yum-devel] multilib preference patch

[seth vidal]

With the help of Tim and James A. I have a patch which lets the user
select what will happen when they are on a multilib arch and they do an:
install foo or install foo* as to which archs it will install by
default.

the config parameter is multilib_policy and it's options are best and
all.

all == the behavior yum has always had - which is to install all archs
it can (ie: i386 and x86_64)

best == install only the 'best' arch for that architecture. So on x86_64
it is x86_64, on ppc64 it should be ppc, on sparc64 it is is sparcv9,
etc

The default is 'all'

This patch also handles removing ia64 as multilib arch b/c it no longer
is one.

It also deals with a small problem with the earlier rpmsack patch from
Florian. 

I feel like we probably want this, but I'm open to opinions.

-sv