xb_manager.backup_inc fails on copying log file

[Valentine Gostev]

20120717-034537 ERROR: test_ib_incremental (xb_incremental_test.basicTest)
20120717-034537 ----------------------------------------------------------------------
20120717-034537 Traceback (most recent call last):
20120717-034537 File "/root/qp/percona_tests/xbm/xb_incremental_test.py", line 52, in test_ib_incremental
20120717-034537 backup1 = xb_manager.backup_inc(master_server, backup0)
20120717-034537 File "/root/qp/lib/util/xb_manager.py", line 143, in backup_inc
20120717-034537 print(os.listdir(self.b_path))
20120717-034537 OSError: [Errno 2] No such file or directory: '/root/qp/workdir/backups/backup1'