proposed fix for using stdin with sub-parsers.
proposed fix for using stdin with sub-parsers.

aerrami/mtools,ces0712/mtools,corymintz/mtools,devkev/mtools,yaowenqiang/mtools,tomzhang/mtools,parkhyeonghwa/mtools,ces0712/mtools,tomzhang/mtools,tomzhang/mtools,gormanb/mtools,gormanb/mtools,rueckstiess/mtools,rueckstiess/mtools,aerrami/mtools,parkhyeonghwa/mtools,corymintz/mtools,ces0712/mtools,gormanb/mtools,yaowenqiang/mtools,aerrami/mtools,corymintz/mtools,yaowenqiang/mtools,devkev/mtools,devkev/mtools,parkhyeonghwa/mtools