fix potential load/save bug
fix potential load/save bug


Former-commit-id: 63424bf0ea7515868cef43cffa8c9749e877149a
clab/cnn,xunzhang/dynet,shuheik/dynet,clab/dynet,clab/dynet,danielhers/dynet,clab/dynet,shuheik/dynet,danielhers/dynet,clab/dynet,xunzhang/dynet,danielhers/dynet,chunyang-wen/dynet,danielhers/dynet,shuheik/dynet,clab/dynet,shuheik/dynet,chunyang-wen/dynet,shuheik/dynet,chunyang-wen/dynet,clab/cnn,danielhers/dynet,chunyang-wen/dynet,shuheik/dynet,danielhers/dynet,danielhers/dynet,clab/dynet,xunzhang/dynet,clab/dynet,xunzhang/dynet,clab/cnn,shuheik/dynet