why I wrote this script, since I don't have all the packages sources!@
the goal of this scrtipt is :
1) clean all file's checksum which already managed by git
(means file's checksum belong to this overlay will be removed)
2) keep the source code/tarballs/patch which should fetch from external
(means file not belong to this overlay need to be preserved)
hope I don't break anything
Signed-off-by: Lan Yixun <dennis.yxun@gmail.com>