httplib2 uses an on-disk cache whose path is given by the
first argument to the httplib2.Http constructor. The `(host)`
parameter was left over from some earlier edition of this
code that didn't do on-disk caching.

Bug: 705046
Change-Id: I061324e4d1bbd680502230aefc73fe66daccaba1
Reviewed-on: https://chromium-review.googlesource.com/458967Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Aaron Gable <agable@chromium.org>