How to fix libvirtError: internal error: Cannot find suitable emulator for x86_64

Fix:
$service apparmor teardown <=============works

https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/632696

==========Error==========
2017-03-03 19:58:56.513 ERROR oslo_service.service [-] Error starting thread.
2017-03-03 19:58:56.513 TRACE oslo_service.service Traceback (most recent call last):
2017-03-03 19:58:56.513 TRACE oslo_service.service   File "/usr/local/lib/python2.7/dist-packages/oslo_service/service.py", line 722, in run_service
2017-03-03 19:58:56.513 TRACE oslo_service.service     service.start()
2017-03-03 19:58:56.513 TRACE oslo_service.service   File "/opt/stack/nova/nova/service.py", line 144, in start
2017-03-03 19:58:56.513 TRACE oslo_service.service     self.manager.init_host()
2017-03-03 19:58:56.513 TRACE oslo_service.service   File "/opt/stack/nova/nova/compute/manager.py", line 1138, in init_host
2017-03-03 19:58:56.513 TRACE oslo_service.service     self.driver.init_host(host=self.host)
2017-03-03 19:58:56.513 TRACE oslo_service.service   File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 471, in init_host
2017-03-03 19:58:56.513 TRACE oslo_service.service     self._parse_migration_flags()
2017-03-03 19:58:56.513 TRACE oslo_service.service   File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 629, in _parse_migration_flags
2017-03-03 19:58:56.513 TRACE oslo_service.service     live_migration_flags)
2017-03-03 19:58:56.513 TRACE oslo_service.service   File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 605, in _handle_live_migration_auto_converge
2017-03-03 19:58:56.513 TRACE oslo_service.service     if (self._is_post_copy_available() and
2017-03-03 19:58:56.513 TRACE oslo_service.service   File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 587, in _is_post_copy_available
2017-03-03 19:58:56.513 TRACE oslo_service.service     hv_ver=MIN_QEMU_POSTCOPY_VERSION):
2017-03-03 19:58:56.513 TRACE oslo_service.service   File "/opt/stack/nova/nova/virt/libvirt/host.py", line 522, in has_min_version
2017-03-03 19:58:56.513 TRACE oslo_service.service     lv_ver=lv_ver, hv_ver=hv_ver, hv_type=hv_type, op=operator.lt)
2017-03-03 19:58:56.513 TRACE oslo_service.service   File "/opt/stack/nova/nova/virt/libvirt/host.py", line 495, in _version_check
2017-03-03 19:58:56.513 TRACE oslo_service.service     conn = self.get_connection()
2017-03-03 19:58:56.513 TRACE oslo_service.service libvirtError: internal error: Cannot find suitable emulator for x86_64
2017-03-03 19:58:56.513 TRACE oslo_service.service