Two bugs are found
1) image download file path is not correct. So even if file is downloaded
already, it can't be detected.
2) several images now are renamed, such as sato-dev, sato-sdk, we need to change the name
accordingly.
Signed-off-by: Liping Ke <liping.ke@intel.com>
When meeting errors, the return number can't be directly compared with
-1. Actually, it might be represented as 255. The correct way is to
compared it with 0. If the result is non-zero number, we meet error.
This patch is for fixing [BUGID #742]
Signed-off-by: Liping Ke <liping.ke@intel.coom>
