Add shard ID to statsd atom for procstats collection

Without this, RANDOM_ONE_SAMPLE would result in statsd dropping all bar the
first shard. Adding the shard id as a dimension field preserves all the
data.

Bug: 158294266
Test: manual build & test
Change-Id: I94ffb610ef3651f460600e3df6b32c87fc430594
2 files changed