The Broadway revival of “Glengarry Glen Ross,” toplined by Al Pacino, has pushed its opening back by almost a month in the wake of Hurricane Sandy, with a new opening set for early December. Show also will extend its limited run by three weeks.Production had played 11 previews before the storm shut down the Rialto for a few perfs last week. According to “Glengarry” producers, the loss of those performances and the concurrently skedded rehearsals prompted the delay of the show’s Nov. 11 opening. With a slew of Rialto titles opening between now and the end of November — including “The Performers,” “Scandalous,” “A Christmas Story” and “Dead Accounts,” all crowded at either end of Thanksgiving week — producers ended up opting to slide the “Glengarry” date all the way into next month. Not that “Glengarry” needs the critics much anyway. Topliner Al Pacino already proved his formidable box office power with his B.O.-busting 2010 stint in “The Merchant of Venice,” and “Glengarry” instantly began raking in cash as soon as it started previews. For the week ending Oct. 28 the title landed in the Top 10, logging more than $1.1 million from only seven perfs.