Fixed compile error on Linux w/ CUDA
Fixed compile error on Linux w/ CUDA

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