The weeklong private- bus strike in Queens became a campaign issue yesterday when City Council Speaker Gifford Miller blasted Mayor Bloomberg for supposedly ignoring the outer boroughs. "If these were bus lines that served Manhattan, they would never get this kind of treatment from the mayor," said Miller during a visit yesterday to a bus shelter in Ozone Park. Miller, who has all but announced his candidacy for mayor this year, attacked Bloomberg for "leaving 70,000 commuters out in the cold." Drivers and mechanics for two private bus lines — Green and Command — went on strike Jan. 10, demanding...