WASHINGTON (Reuters) - President Barack Obama's lead over Republican Mitt Romney narrowed to 5 percentage points in a Reuters/Ipsos poll released on Monday, from a high of seven points in the week after the Democratic National Convention. With just 50 days before the November 6 election, Obama led the former Massachusetts governor by 48 percent to 43 percent among likely voters in the online poll conducted September 12-17. In a similar poll last Thursday, he led by 48 percent to 41 percent. ...