Initially both metrics collection and publishing were
going to be disabled to work around P0:b/35093325.
But disabling collection was not completed since it proved
to be unnecessary. However, remnants were left in the header
file. This change just cleans up the remnants.
Change-Id: Ibdceafd2add31c93de995a558a675b8ba8a055bc
related-to-bug:35093325
f39c002618