Pin the version of google-api-python-client/oauth2client that we use.

oauth2client 2.0 had a breaking API change, so it's better that we
stick with 1.x if that's what we tested on.  See
googleapis/oauth2client#401

(This affects alertlib for sure, but may also affect us.)

Auditors: tom

Test plan:
Ran the new commands manually on internal-services; we'll see if cron
complains anymore.

requirements.txt

@@ -1,7 +1,7 @@
 Flask>=0.10.1
 redis>=2.10.3
-oauth2client>=1.4.6
-google-api-python-client>=1.3.1
+oauth2client==1.4.6
+google-api-python-client==1.3.1
 numpy
 rpy2