bots: Enable googlesearch bot to run by 'zulip-run-bot' command.

Since we want our bots to be both python 2 and python 3 compatible,
we use six to make up for both of them and run the bot smoothly.

'http.client' was basically used for error-handling by the author
of the bot, urllib errors can be handled by the urllib itself. So,
using this for simplicity.

urllib.request.urlopen raises URLError on protocol errors.

zulip_bots/zulip_bots/bots/googlesearch/googlesearch.py

@@ -1,7 +1,7 @@
 # See readme.md for instructions on running this code.
 from __future__ import print_function
 import logging
-import http.client
+from six.moves.urllib import error
 from six.moves.urllib.request import urlopen
 
 # Uses the Google search engine bindings
@@ -26,7 +26,7 @@ def get_google_result(search_keywords):
         try:
             urls = search(search_keywords, stop=20)
             urlopen('http://216.58.192.142', timeout=1)
-        except http.client.RemoteDisconnected as er:
+        except error.URLError as er:
             logging.exception(er)
             return 'Error: No internet connection. {}.'.format(er)
         except Exception as e:
@@ -85,7 +85,7 @@ def test():
         urlopen('http://216.58.192.142', timeout=1)
         print('Success')
         return True
-    except http.client.RemoteDisconnected as e:
+    except error.URLError as e:
         print('Error: {}'.format(e))
         return False