Stoffel engine change was strategic, not a failure

Vandoorne's v3.8 engine "failed" in FP1 and they reverted to the v3.7 for FP2. Turns out this was more likely to be a strategic move, to use the v3.8 in Mexico to take the penalty but then have it fresh to use in Brazil (as hinted by di Resta in the Sky commentary).

Satoshi Nakamura (HondaF1 Principal Engineer) said, in the [Practice Report] (http://en.hondaracingf1.com/2017/index/mexico-gp-reports.html) - "Stoffel's PU change was more strategic in order to help with reliability for the final two races in Brazil and Abu Dhabi."

He went on to say "We found a potential issue in his data at the beginning of FP1 and decided to change his PU as a precaution. Although it was frustrating to lose most of the session, we found the issue was very minor and there was no damage to the PU". So maybe there was a glitch but it certainly wasn't terminal.