import-metrics: don't fail if index exist
import-metrics: don't fail if index exist

also reformat with black and update schema

criteo/biggraphite,iksaif/biggraphite,Thib17/biggraphite,iksaif/biggraphite,Thib17/biggraphite,criteo/biggraphite,criteo/biggraphite,iksaif/biggraphite,iksaif/biggraphite,Thib17/biggraphite,criteo/biggraphite,Thib17/biggraphite