fix warnings
fix warnings

Abasyoni/dynet,mitchellstern/dynet,yoavg/cnn,Abasyoni/dynet,dhgarrette/cnn,cherryc/dynet,Peilun-Li/dynet,dhgarrette/cnn,Peilun-Li/dynet,cherryc/dynet,dhgarrette/cnn,kamigaito/cnn,yoavg/cnn,cherryc/dynet,mitchellstern/dynet,Peilun-Li/dynet,kamigaito/cnn,Abasyoni/dynet