plugins: rename 'filter' method in BUCK file
plugins: rename 'filter' method in BUCK file

The name 'filter' overrides a python built-in method.

Change-Id: I187d4d34a9c757d76d76d7707156c7482ea59fb4

joshuawilson/merrit,WANdisco/gerrit,qtproject/qtqa-gerrit,MerritCR/merrit,joshuawilson/merrit,WANdisco/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,MerritCR/merrit,WANdisco/gerrit,qtproject/qtqa-gerrit,MerritCR/merrit,MerritCR/merrit,GerritCodeReview/gerrit,gerrit-review/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,joshuawilson/merrit,GerritCodeReview/gerrit,MerritCR/merrit,GerritCodeReview/gerrit,joshuawilson/merrit,MerritCR/merrit,gerrit-review/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,MerritCR/merrit,gerrit-review/gerrit,WANdisco/gerrit,MerritCR/merrit,gerrit-review/gerrit,gerrit-review/gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,gerrit-review/gerrit,joshuawilson/merrit,joshuawilson/merrit,qtproject/qtqa-gerrit,WANdisco/gerrit,WANdisco/gerrit,joshuawilson/merrit,WANdisco/gerrit,gerrit-review/gerrit,joshuawilson/merrit