Remove apiclient.__version__ (#871)

Hello,

We have removed __version__ var from googleapiclient/__init__.py
f706cfd#diff-b926d296d4c856bcbf877809e4523562L15
so it won't work anymore.

#870

CC: @busunkim96
Fixes #870 🐈

Author: mik-laj

apiclient/__init__.py

@@ -19,8 +19,6 @@
     sample_tools = None
 from googleapiclient import schema
 
-__version__ = googleapiclient.__version__
-
 _SUBMODULES = {
     "channel": channel,
     "discovery": discovery,