closes #1864, mock grpcio when generating docs.

Author: daspecster

docs/conf.py

@@ -23,6 +23,7 @@
 ON_READ_THE_DOCS = os.environ.get('READTHEDOCS', None) == 'True'
 LOCAL_READ_THE_DOCS = os.environ.get('LOCAL_RTD', None) == 'True'
 
+
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.

setup.py

@@ -25,7 +25,7 @@
     'gax-google-pubsub-v1',
 ]
 
-if sys.version_info[:2] == (2, 7):
+if sys.version_info[:2] == (2, 7) and 'READTHEDOCS' not in os.environ:
     REQUIREMENTS.extend(GRPC_EXTRAS)
 
 setup(