git-codereview: accept more forms of hosts in cookies file

If the user selects "all of googlesource.com" option when generating
the password, the host will be ".googlesource.com", the tool needs
to also support this form.

Change-Id: Id2669e4b7a7b137c9b99399dbfb8c14dd330b368
Reviewed-on: https://go-review.googlesource.com/1771
Reviewed-by: Russ Cox <rsc@golang.org>