KVM Test: Extend migration test to test unix, exec and migrate_cancel

Update migrate() in kvm_test_utils.py to support unix, exec protocol and
migration cancel test.
Add four migration sub test. There are tcp, unix, exec and mig_cancel.
migrate_cancel only work in tcp protocol.
For exec protocol, we need first save VM status to a file, then load the status
file to dest VM.

Note:
for_migration parameter in create() in kvm_vm.py is useless now.
Corresponding code have been deleted from create(). Keep this parameter in 
order to keep interface stability. It may be delete later. Please use
extra_params for migration.

Signed-off-by: Feng Yang <fyang@redhat.com>


git-svn-id: http://test.kernel.org/svn/autotest/trunk@4629 592f7852-d20e-0410-864c-8624ca9c26a4
4 files changed