Fixed libvirt bad exception when destroying a VM.

Libvirt raises an exception saying "domain not runnning" when trying to destroy
a VM that is in fact running. So we try to figure out if this is this kind of
exception and we ignore it in this case.

ccnode/hypervisor/__init__.py

@@ -200,9 +200,13 @@ class Handler(HostHandler):
         logger.debug('VM destroy %s', name)
         try:
             self.hypervisor.domains[name].destroy()
-        except libvirt.libvirtError:
-            logger.exception('Error while destroying VM %s', name)
-            raise
+        except libvirt.libvirtError as exc:
+            # Libvirt raises exception 'domain is not running' event is domain
+            # is running, might be a bug in libvirt
+            if 'domain is not running' not in str(exc) or (
+                self.hypervisor.domains[name].state != 'running'):
+                logger.exception('Error while destroying VM %s', name)
+                raise
         except KeyError:
             msg = 'Cannot destroy VM %s because it is not defined' % name
             logger.error(msg)