Fix the case where neither vc nor sdk script exist or, vc doesn't work and sdk doesn't exist.
Fix the case where neither vc nor sdk script exist or, vc doesn't work and sdk doesn't exist.

timj/scons,timj/scons,andrewyoung1991/scons,timj/scons,andrewyoung1991/scons,timj/scons,timj/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,timj/scons,timj/scons,andrewyoung1991/scons,andrewyoung1991/scons,timj/scons,timj/scons