Long & Foster has bought a northern Virginia real estate firm, its second deal since being acquired by an affiliate of Berkshire Hathaway in September. Terms of the deal for Herndon-based McGrath Real Estate Services were not disclosed. McGrath's real estate sales division and its property management division will join their respective Long & Foster counterparts. McGrath's Herndon office will become a Long & Foster office. Jim and Tim McGrath, owners of McGrath Real Estate Services, will take...