attach old sha1 to the comment in new repo

[meihuaping]

Attach old sha1 to the comment in new repo.Show like below:
before converted:
commit 86af00687ffd455c3c5e54c67864f6a8fee8e3f0(old sha1)
Author: cjp service@t-firefly.com
Date: Wed Feb 22 18:00:38 2017 +0800

kernel->file: ignore some file

after converted:
commit 86af00687ffd455c3c5e54c67864f6a8fee8e3f1(new sha1)
Author: cjp service@t-firefly.com
Date: Wed Feb 22 18:00:38 2017 +0800

kernel->file: ignore some file
86af00687ffd455c3c5e54c67864f6a8fee8e3f0(old sha1)