Fix bug in which conv kernel thread count could be None.
Fix bug in which conv kernel thread count could be None.

coufon/neon-distributed,dongjoon-hyun/neon,NervanaSystems/neon,NervanaSystems/neon,Jokeren/neon,NervanaSystems/neon,dongjoon-hyun/neon,Jokeren/neon,NervanaSystems/neon,dongjoon-hyun/neon,Jokeren/neon,coufon/neon-distributed,coufon/neon-distributed,Jokeren/neon