virttest.utils_misc:fix 'unknown' CPU for IBM Power architecture

Currently, virt-tests support amd and intel's X86 cpu type,
IBM Power cpus will be detected as 'unknown'.

To solve the problem, use platform.machine, so when the
arch is ppc64, we can return appropriate power CPU models.

Signed-off-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
virttest.utils_misc:fix qemu-system-ppc64 cpu model list

Currently, the regular expression in extract_qemu_cpu_models just
works with X86 qemu models.

Add check if X86 pattern return none, will use PowerPC pattern to
get qemu support cpu model.

If it is not possible to recognize the patterns in
the output of 'qemu -cpu ?', throw an error explaining
that the proper support must be added.

Signed-off-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
guest-os:add the fedora17 and 18 for ppc64 guest os support

Currently, the autotest haven't support the guest os fedora17
and 18 for ppc64.

Add two config file to support this to os.

Signed-off-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
virt:Fix check_modules error for other arch

Currently, check_modules in qemu/get_started.py and
virttest/standalone_test.py just suitable for x86_64, for other
arch, especially ppc64, will not have module like kvm-%s, and this
causes errors.

To fix this problem, use platform to decide the modules need to
be checked.

Signed-off-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
Introduce arch module

In order to concentrate (as much as possible) processor
architecture dependent code, create an arch module on
virt tests. As the first function in there, refactor
the code that gets the list of kvm modules on different
architectures.

The idea is to move other arch dependent code to that
module, so we have a cleaner and less repetitive way
of solving multi-arch support.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
arch: Add arch dependent networking constants

As mentioned, it'll be better and easier to have as much
as possible of the arch dependent code in this module.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>