The statute says that only the U.S. Attorney or the Attorney General can file a quo warranto action without prior court approval. Anyone else has to first ask the Attorney General to file, and, if the AG refuses, has to ask the court's permission to file. The court will allow it to be filed only if the requester is a "person interested" and only if the petition is "sufficient in law."
I am willing to bet that when Leo Donofrio files, the court will say that he is not a person interested and that his petition is not sufficient in law, and will cite Judge Land's and Judge Carter's decisions as precedent. But time will tell.
Its interesting to note that both the United States Attorney General and the US Attorney for the District of Columbia are African-Americans and Democrats.