Bug fix #360: Support i686 architecture

The i686 architecture was not being recognized while creating a template:

File "/usr/lib/python2.7/dist-packages/kimchi/vmtemplate.py", line 64, in init
entry = osinfo.lookup(os_distro, os_version)
File "/usr/lib/python2.7/dist-packages/kimchi/osinfo.py", line 114, in lookup
if distro in modern_version_bases[arch]:
KeyError: None

Fix it.

Signed-off-by: Ramon Medeiros <ramonn@linux.vnet.ibm.com>