run: Make the default QEMU set stricter

The default QEMU set, migrate, can usually be run with
a variety of QEMU shipped by current distros.

With the new migration protocols, people running the
default set will frequently have SKIPPED tests, which
is not good. So, restrict the default set to
protocols that are widely available. Once the new
formats are widespread (could take over a year for
that to happen), we can revert this change.
Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>