Change invalid root from LOG(ERROR) to LOG(INTERNAL_FATAL)

INTERNAL_FATAL is more likely to remain in bug reports.

(cherry picked from commit 175746ac9039e9b741d3521420dcaa9c59341738)

Bug: 20736048
Change-Id: I518f079d8d1839e22b3595e807730edf36318f1d
1 file changed