Fix untranslated log messages in libvirt driver

[Aswad Rangnekar]

Some log messages in libvirt driver are not translated. These message should be wrapped in _("") wrapper.

Shown below are occurrences in libvirt driver.
nova/virt/driver.py:962: LOG.debug("Discarding event %s" % str(event))
nova/virt/driver.py:970: LOG.debug("Emitting event %s" % str(event))
nova/virt/libvirt/driver.py:472: LOG.debug("Event loop thread is not active, "
nova/virt/libvirt/driver.py:545: LOG.debug("Starting native event thread")
nova/virt/libvirt/driver.py:550: LOG.debug("Starting green dispatch thread")
nova/virt/libvirt/driver.py:583: LOG.debug("Registering for lifecycle events %s" % str(self))
nova/virt/libvirt/driver.py:595: LOG.debug("Registering for connection events: %s" %
nova/virt/libvirt/driver.py:1820: LOG.debug("This python runtime does not support direct I/O")

[Aswad Rangnekar (aswad-r)]

Submitted path for review : https://review.openstack.org/#/c/42323/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/42323
Committed: http://github.com/openstack/nova/commit/fb2534deefd40d14704bfee523ce890e88e65c7c
Submitter: Jenkins
Branch: master

commit fb2534deefd40d14704bfee523ce890e88e65c7c
Author: Aswad Rangnekar <email address hidden>
Date: Wed Aug 14 05:06:28 2013 -0700

    Fix untranslated log messages in libvirt driver

    Fixes bug 1213040

    Change-Id: Ib3b7a46c312b88778cc6e872a2c19061a5774125