issue0017: retrun error when get ftp conn error

Change-Id: Ib0b3529bb53cf2ecb4ca7f93fbe9010621bd034a
issue0018: query teststatus without signal

1. if cannot query the task info, cancel task
2. transfer exit after 60s without task
3. md5 error, retry

Change-Id: Ie81a041740b312446b6a506f16faf0b1a32b30c2