title: ImportError:cannot import name symbol_database
body: <p>I'm new to caffe.When I try the caffe,the problem occurs.Anyone can help?Thanks in advance!</p>
  
  <pre><code>&gt;&gt;&gt; import google.protobuf
  &gt;&gt;&gt; import caffe
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/home/llzxo/caffe/python/caffe/__init__.py", line 1, in &lt;module&gt;
      from .pycaffe import Net, SGDSolver, NesterovSolver, AdaGradSolver, RMSPropSolver, AdaDeltaSolver, AdamSolver
    File "/home/llzxo/caffe/python/caffe/pycaffe.py", line 15, in &lt;module&gt;
      import caffe.io
    File "/home/llzxo/caffe/python/caffe/io.py", line 8, in &lt;module&gt;
      from caffe.proto import caffe_pb2
    File "/home/llzxo/caffe/python/caffe/proto/caffe_pb2.py", line 10, in &lt;module&gt;
      from google.protobuf import symbol_database as _symbol_database
  ImportError: cannot import name symbol_database
  </code></pre>