Make timeout value apply to entire job

Rather than have the job timeout apply to each of the three run steps
(pre, run, and post) individualy convert the timeout to a cummulative
timeout that applies across all three steps. This is more intuitive to
users and allows us to continue to have long job timeouts without
multiplying their effect when things go wrong.

Change-Id: I8f46736e578c8ea3e9f2fba25f53ab47715101af
1 file changed