Boston Mayor Tom Menino is trying to block the city’s historic opera house from slapping a new corporate name on its facade. Citizens Bank paid $4 million to buy the naming rights to the recently reopened venue, but the mayor and several other elected officials have objected, saying that the theatre should continue to be known simply as the Opera House. Furthermore, Clear Channel, which bought and renovated the venue with considerable assistance from Menino, says that it “owes” the mayor, and may be amenable to squelching the naming deal.