bug#32583: Cuirass: some builds are marked as failed, but they were never built

["Clément Lassieur" <clement@lassieur.org>]

Reported by Ludovic on IRC.

Some builds are marked as failed, but they were never built.  Plus,
starttime and stoptime don't make sense.

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<civodul> snape: i just noticed something fishy:
	  https://berlin.guixsd.org/build/467599 is marked as failed
								        [11:24]
<civodul> however,
	  /gnu/store/nr0w89qymmnfbcb9vw9q86p0a4v1h6w2-libsvgtiny-0.1.7.drv has
	  never been built
<civodul> so it's not even a dependency-failed situation
<civodul> i wonder if this could be a regression in Cuirass
<civodul> it has "starttime":0,"stoptime":1535613271  [11:25]
<civodul> which normally cannot happen (starttime shouldn't be 0 i stoptime is
	  not 0)
<snape> civodul: indeed it's weird  [11:27]
<snape> civodul: how do you know
	/gnu/store/nr0w89qymmnfbcb9vw9q86p0a4v1h6w2-libsvgtiny-0.1.7.drv has
	never been built?  [11:28]
<snape> well, I guess because there is no log  [11:32]
<civodul> snape: yes and i ssh'd into berlin
<snape> civodul: it builds if you spawn it manually?  [11:37]
<civodul> snape: i didn't let it run to completion because i wanted us to be
	  able to debug it  [11:39]
<civodul> but most likely it does  [11:40]
<civodul> (i tested with
	  /gnu/store/wgk46pv09m1y8b7iq5fbkhay5hs6hnmr-libcss-0.8.0.drv, which
	  was another build marked as failed)
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Clément