the last pooling size mismatch

[zhangkaij]

the last pooling size is not inconsistent with paper.
in the paper:
the size of the pooling7 feature map = 1*1
in model_libs.py:
the size of the pooling7 feature map = 2*2

Also, DSOD prediction layers differ from the figure 1 in paper.

[szq0214]

Hi @zhangkaij, thanks for pointing out this! I will correct it in our revision.