I have a take on this, it might have more to do with this,
SEATTLE , Nov. 30, 2011 /PRNewswire/ -- Boeing (NYSE: BA - News) today announced that it intends to build the new 737 MAX in Renton, Wash. , pending approval of an early contract extension with the International Association of Machinists & Aerospace Workers (IAM), the union representing hourly employees in Washington , Oregon and Kansas .
As part of an effort to improve their relationship, Boeing and the IAM have been discussing the potential for an early contract extension for several weeks. The current contract is set to expire in September 2012 .
Boeing Announces Intent to Locate 737 MAX Production in Puget Sound - Yahoo! Finance
A couple of things come to mind here, first the 787 production in Washington is well ahead of the production in S.C. which should deliver it's first aircraft by June of next year. The other thing is that the 737 MAX which is the next gen. of the 737 will be a a huge seller for Boeing and will provide long term employment at Boeing for many many years to come, so perhaps the reason the suit was dropped was because the 787 production line in S.C. became less and less an issue when it came to jobs?