Delete warnings from request-pull output

I'm not actually generating a pull request. It's generated just for
review. And git shows warnings because request-pull is not used
properly.
Header for PullRequest diff
:GllogPatch shows PR commits if executed from diff chunk

If :GllogPatch is executed from code chunk in Pull Request diff mode, it
shows all commits, that touched corresponding file, between base branch
and head branch.