Use single underscore variable in loop iteration(in compute)

This is to do the same cleanup in identity as
Ie83d6533a6566a22ca78f9ea60a7be1c94531065,
when loop variable is not really used, then use
single underscore as the variable name.

Change-Id: If9129d60f629fb424b809ca5aa4c6b8167a7d16a
9 files changed