Fix the way metrics are handled for deletions.

[manishrjain]

This change is 

[manishrjain]

Feel free to merge. One comment.

Reviewable status: 0 of 4 files reviewed, 1 unresolved discussion (waiting on @jarifibrahim)

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policy.go, line 294 at r2 (raw file):

		p.metrics.add(keyUpdate, key, 1)
		p.metrics.add(costAdd, key, ^uint64(uint64(prev)-1))
		p.metrics.add(costAdd, key, uint64(cost))

Do it in one op.

[poonai]

Reviewed 3 of 4 files at r1, 1 of 1 files at r3.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @jarifibrahim)

[jarifibrahim]

Reviewed 3 of 4 files at r1, 1 of 1 files at r3.
Dismissed @manishrjain from a discussion.
Reviewable status: complete! all files reviewed, all discussions resolved

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policy.go, line 294 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Do it in one op.

Done by @balajijinnah