Allow `pkg.latest_version` to work for `i386`.

```
[root@cent5-test /]# yum list *xz-devel*
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * epel: fedora-epel.mirror.lstn.net
Available Packages
xz-devel.i386                      4.999.9-0.3.beta.20091007git.el5                    base
xz-devel.x86_64                    4.999.9-0.3.beta.20091007git.el5                    base
```

```
[root@cent5-test testing]# salt-call pkg.latest_version xz-devel.x86_64
local:
    4.999.9-0.3.beta.20091007git.el5

[root@cent5-test testing]# salt-call pkg.latest_version xz-devel
local:
    4.999.9-0.3.beta.20091007git.el5

[root@cent5-test testing]# salt-call pkg.latest_version xz-devel.i386
local:
```

And with this fix:
```
[root@cent5-test /]# salt-call pkg.latest_version xz-devel.i386
local:
    4.999.9-0.3.beta.20091007git.el5
```