Reseller admins can set new headers on accounts like
X-Account-Quota-Bytes-Policy-<policy-name>: <quota>
This may be done to limit consumption of a faster, all-flash policy, for
example.
This is independent of the existing X-Account-Meta-Quota-Bytes header, which
continues to limit the total storage for an account across all policies.
Change-Id: Ib25c2f667e5b81301f8c67375644981a13487cfe