* Williams dismisses Errani, Sharapova beats Ivanovic * Number one ranking on the line in Sunday’s final (Adds Sharapova result, quotes, byline) By Iain Rogers MADRID, May 11 (Reuters) – Serena Williams’ tactic of staying in her hotel room and being “boring†appears to be paying off after the world number one swept past Sara Errani on Saturday to set up a Madrid Open final against rival Maria Sharapova. …
