Bug 898554 - Run hazard commands under mock when needed, r=jlund

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extra : rebase_source : a7e2d32ba7c95d783ce938db351ca917854f4507
Bug 898554 - Remove verbose sixgill warning message that makes the log file overflow the size cap

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extra : rebase_source : 16ee08a1cdd1eb8bb74cb081c0ed72833c2b9793