Fixed clang compile error wrt mismatched types
Fixed clang compile error wrt mismatched types


Former-commit-id: 10f32f8eb42658c9645020bcc9e3fca96093c117
xunzhang/dynet,xunzhang/dynet,clab/cnn,chunyang-wen/dynet,xunzhang/dynet,shuheik/dynet,shuheik/dynet,clab/dynet,clab/cnn,chunyang-wen/dynet,shuheik/dynet,danielhers/dynet,chunyang-wen/dynet,danielhers/dynet,shuheik/dynet,danielhers/dynet,clab/dynet,chunyang-wen/dynet,danielhers/dynet,shuheik/dynet,xunzhang/dynet,clab/dynet,shuheik/dynet,danielhers/dynet,danielhers/dynet,clab/cnn,shuheik/dynet,danielhers/dynet,clab/dynet,clab/dynet,clab/dynet,clab/dynet