PRECIOUS-Gold slips as trade optimism lifts risk assets; ECB meet in focus

* Palladium set for 4th session of gains (Adds technicals, updates prices) By Karthika Suresh Namboothiri Spot gold XAU= was down 0.1% at $1,495.30 per ounce, as of0528 GMT. U.S. gold futures GCcv1 …