[#2029] Add lint branch name via command line.


Problem description
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When we run the linter on buildslave, that git repo is barebone repo and does not carry branch name.



Changes description
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Add a branch command line option to linter.

After this is relese we need to update brink version in repos and then also update buildbot to send branch name as command line.


How to try and test the changes
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reviewers @alibotean 

Add a #FIXME marker with current branch and run linter.
Add a FIXME for another branch and run paver lint -b ID-branch-name ... you should see warnings.