When read_affinity is used and sorting_method is not used warnings
are generated in the swift proxy log indicating that the
read_affinity is not being respected. When read_affinity is specified
this change sets the sorting_method to affinity automatically, and
otherwise uses a configured value which defaults to shuffle.
Note that write_affinity does not respect sorting_method and follows
a different code path and does not issue warnings in logs when used
without sorting_method.
Closes-bug: 1480581
Co-Authored-By: Andy McCrae <andy.mccrae@gmail.com>
Change-Id: I3cab89c95f288b4a59f4dd3c7360daca7a4f47bf
39b0e5d443