container: Unify storage-policy error paths
container: Unify storage-policy error paths

While we're at it, use the right header name.

Change-Id: I2238ec7fb0325167c53757b62ff9eb2ce5576fa4

openstack/swift,tipabu/swift,openstack/swift,swiftstack/swift,swiftstack/swift,tipabu/swift,tipabu/swift,openstack/swift,tipabu/swift,openstack/swift,swiftstack/swift