lisa/wa_results_collector: Fix parse_traces=True
Created by: valschneider
Daniel pointed out that passing parse_traces=True
to
WaResultsCollector breaks horribly on a sad piece of code.
We're attempting to create a PlatformInfo to give to Trace, but we're only filling it with the kernel version which mostly useless. Just skip that step, and only pass a non-None platinfo if the user specified one.
Ideally we should collect one platform_info per wa directory, but that would mean adding a LISA-specific step to lisa-wltest which I think we all would like to avoid.