Add debug in live migration

cloudcontrol/node/hypervisor/__init__.py

@@ -418,10 +418,12 @@ class Handler(HostHandler):
                     0,
                 )
             except libvirt.libvirtError:
+                sys.stderr('libvirt error during migration\n')
                 traceback.print_exc(file=sys.stderr)
                 os._exit(1)
             except:
                 # whatever the matter is we MUST NOT return to libev or sjRPC
+                sys.stderr('error during migration\n')
                 traceback.print_exc(file=sys.stderr)
                 os._exit(2)
             else: