migration: Rename save_live_setup() to save_setup()

We are going to use it now for more than save live regions.
Once there rename qemu_savevm_state_begin() to qemu_savevm_state_setup().

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170628095228.4661-2-quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>