METALS-London copper off three-week low, but trade worries drag

(Adds analyst comment, updates prices) By Manolo Serapio Jr MANILA, June 20 (Reuters) - London copper prices steadied on Wednesday after touching a three-week low earlier in Asian trading, but a deepening trade row between China and the United States capped any recovery in risk appetite. Other metals including aluminium and zinc also edged up, but were not far above multi-week lows reached on Tuesday. "While the (trade) tariffs in themselves don't derail the narrative of global