Bug 885331 - added PYTHONPATH in doPartnerRepacks env. r=nthomas

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extra : amend_source : 48a0f5ea7deae4f0ab50e59845f2c3275fb19ab9
Bug 1074826 - Clean up some pyflakes & PEP8 warnings in buildbotcustom; r=pmoore
Bug 1087574: remove unused TalosFactory code. r=Callek
Bug 1087574: Remove unused steps r=Callek