v2v: Fall back to virDomainGetInfo if remote libvirtd does not support virDomainGetState (RHBZ#1138586).

RHEL 5 Xen doesn't support the relatively new virDomainGetState API.
Instead you will see a warning message on stderr:

  libvirt: Remote Driver error : unknown procedure: 212

If we detect that virDomainGetState is not supported, then fall back
to calling virDomainGetInfo instead, which works everywhere.

This updates commit 096c05a750b8b525e48149c0c6522769c92ab07c.

See also:
https://bugzilla.redhat.com/show_bug.cgi?id=1139973#c2
https://bugzilla.redhat.com/show_bug.cgi?id=1138586