Suppress unnecessary "frame not found" errors.

ConsumerFrameEventHistory only stores 8 frames of history,
but video can queue more than 8 frames, which triggers
some annoying ALOGE messages that aren't really errors.

This patch makes sure to print the error only if the
producer has enabled the frame events, which only happens
with EGL where we won't see more than 3 frames queued.

Test: This only affects error reporting.

Change-Id: I184202a71f5fe29159c148957b92fb2e856bf625