a bug when import codes from original repo to another

[xialonglee]

there is a bug waiting for fixed

if a man import some codes from one repository to another, like this pr:
kubernetes/community /pull/118 ( i don't want make a link points to that pr , it will notice the participants in that pr )
the pr imported some docs form repo kubernetes/kubernetes to repo kubernetes/community with commit logs
so a person who commit in repo kubernetes/kubernetes now will have a copy in kubernetes/community too(but different SHA, i.e. you have tow commits are totally same but different SHA in two repos). in this case , the author and the committer of these two commits are same, so here comes the problem.
the scheme that we find a pr form a commit is that :

1. seaching a pr from commit's SHA with repos and author name specified , if not found , it may be the case that the committer and the author are not the same, go step 2
2. seaching a pr from commit's SHA, but now change author name to committer .
   but according this scheme can not pr in the situation i mention above, so i think we should add a step 3 that do not specified the author arg

i also doubt whether it is reduntant that specified author arg when searching pr. may be specified repos arg is enough. if returns many, we could filter them by author's name.

@bruceauyeung