Quotas for users with admin role do not work

The quotas code does not isloate counts to resources within the
current tenant/project.  So if a user with the admin role makes
calls for quota items, the admin role will have counts of a global
list of resources.  This changes that for the tenant quota call
to fallback to the request.user.project_id if no project was
otherwise specified for the tenant quota api call.

Change-Id: Ib0e6ce7774c4c03686a044f233dbb9aa36dbe1b9
Closes-bug: #1391242
Merge "Quotas for users with admin role do not work"