This change updates the account HEAD handler to report out per
policy object and byte usage for the account. Cumulative values
are still reported and policy names are used in the report
out (unless request is sent to an account server directly in
which case policy indexes are used for easier accounting).
Below is an example of the relevant HEAD response for a cluster
with 3 policies and just a few small objects:
X-Account-Container-Count: 3
X-Account-Object-Count: 3
X-Account-Bytes-Used: 21
X-Storage-Policy-Bronze-Object-Count: 1
X-Storage-Policy-Bronze-Bytes-Used: 7
X-Storage-Policy-Silver-Object-Count: 1
X-Storage-Policy-Silver-Bytes-Used: 7
X-Storage-Policy-Gold-Object-Count: 1
X-Storage-Policy-Gold-Bytes-Used: 7
Set a DEFAULT storage_policy_index for existing container rows during
migration.
Copy existing object_count and bytes_used in policy_stat table during
migration.
DocImpact
Implements: blueprint storage-policies
Change-Id: I5ec251f9a8014dd89764340de927d09466c72221