[starvation] fix bug in starting location of trace
[starvation] fix bug in starting location of trace

Summary: The trace starts always at a dummy location. Fix.

Reviewed By: ezgicicek

Differential Revision: D17981065

fbshipit-source-id: 2807a04fe

jvillard/infer,facebook/infer,jvillard/infer,jvillard/infer,facebook/infer,facebook/infer,jvillard/infer,facebook/infer,jvillard/infer,facebook/infer,jvillard/infer,facebook/infer,facebook/infer,jvillard/infer