Delete mockdynet.py
Delete mockdynet.py

Former-commit-id: 83286462ffe6809d3525e9a48cfb7cefcd97c9d0
shuheik/dynet,shuheik/dynet,clab/cnn,xunzhang/dynet,chunyang-wen/dynet,danielhers/dynet,clab/dynet,danielhers/dynet,chunyang-wen/dynet,xunzhang/dynet,clab/dynet,danielhers/dynet,xunzhang/dynet,clab/dynet,danielhers/dynet,clab/dynet,clab/dynet,clab/cnn,shuheik/dynet,chunyang-wen/dynet,shuheik/dynet,clab/dynet,danielhers/dynet,chunyang-wen/dynet,shuheik/dynet,shuheik/dynet,shuheik/dynet,danielhers/dynet,clab/cnn,clab/dynet,danielhers/dynet,xunzhang/dynet