Bug 1103123 - Update runner to 1.5; r=rail

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extra : rebase_source : 8db97b9d9f0e18eabf722c101da1220b7afc2f43
Bug 1103123 - Force runner to reboot the machine after 30 iterations; r=rail

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extra : rebase_source : c0933a3cf25be62ada7843dd45f899b54282840e
Bug 1103123 - Add post-flight runner task to linux slaves; r=rail

This task selectively triggers runner's halt task; which will reboot the machine.
This may be acheived via hostname blacklisting or discovery that a job has failed.