[PATCH] relax check regex for revert commit

[Jia He]

For revert commit, it might has two double quotation marks in its
commit log.
Relax the check condition for revert commit to avoid checkpatch
errors.

Without this patch, checkpatch.pl will report errors:
ERROR: Please use git commit description style
...

Attached testcases here:
[test case 1] test single line revert commit
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