I am getting following error without this commit when doing docker build.

  File "<string>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/setuptools/__init__.py", line 12, in <module>
    import setuptools.version
  File "/usr/local/lib/python2.7/dist-packages/setuptools/version.py", line 1, in <module>
    import pkg_resources
  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 70, in <module>
    import packaging.version
ImportError: No module named packaging.version

No idea why this change fix the problem, but it does fix.

SparseGpuMatrix::mul(GpuMatrix, GpuMatrix),
CpuMatrix::mul(CpuSparseMatrix, CpuMatrix),
and GpuMatrix::mul(GpuSparseMatrix, GpuMatrix)

and GpuMatrix::mul(CpuMatrix, GpuSparseMatrix)

Also initialize glog after gflags in Util.cpp initMain()

Change-Id: I09ff062b462aa76d9f7b5f97e883b92939e6dcb2

* update function can not be inherited since updateImpl exsits
* remove update implementation in one inherited updater