This patch adds the erasure code reconstructor. It follows the
design of the replicator but:
 - There is no notion of update() or update_deleted().
 - There is a single job processor
 - Jobs are processed partition by partition.
 - At the end of processing a rebalanced or handoff partition, the
 reconstructor will remove successfully reverted objects if any.
And various ssync changes such as the addition of reconstruct_fa()
function called from ssync_sender which performs the actual
reconstruction while sending the object to the receiver
Co-Authored-By: Alistair Coles <alistair.coles@hp.com>
Co-Authored-By: Thiago da Silva <thiago@redhat.com>
Co-Authored-By: John Dickinson <me@not.mn>
Co-Authored-By: Clay Gerrard <clay.gerrard@gmail.com>
Co-Authored-By: Tushar Gohad <tushar.gohad@intel.com>
Co-Authored-By: Samuel Merritt <sam@swiftstack.com>
Co-Authored-By: Christian Schwede <christian.schwede@enovance.com>
Co-Authored-By: Yuan Zhou <yuan.zhou@intel.com>
blueprint ec-reconstructor
Change-Id: I7d15620dc66ee646b223bb9fff700796cd6bef51