[tests] Only use 2 processes for ring.
[tests] Only use 2 processes for ring.

victorisildur/Graphite,victorisildur/Graphite,8l/Graphite,8l/Graphite,8l/Graphite,victorisildur/Graphite,victorisildur/Graphite,nkawahara/Graphite,fhijaz/Graphite,fhijaz/Graphite,8l/Graphite,mit-carbon/Graphite,nkawahara/Graphite,nkawahara/Graphite,mit-carbon/Graphite,mit-carbon/Graphite-Cycle-Level,mit-carbon/Graphite,mit-carbon/Graphite-Cycle-Level,fhijaz/Graphite,fhijaz/Graphite,mit-carbon/Graphite,nkawahara/Graphite,mit-carbon/Graphite-Cycle-Level,mit-carbon/Graphite-Cycle-Level