By Chris Herring For fans of a league where player movement is on the rise, buying NBA jerseys is more challenging than ever. There have been times throughout the years when parts of Rockets fan Allison Wollam’s walk-in closet look like an unofficial tribute to the Houston basketball heroes who’ve fallen by the wayside. A 46-year-old diehard who fell in love with her hometown team during the club’s back-to-back title run in the mid-1990s, Wollam made a point to start collecting jerseys in the early 2000s. She amassed several during that era, including stars such as Yao Ming and Steve Francis, …