Add procstat input for dockerd

Change-Id: I8457d10b2150bda0f417d891550ff854f36ab26c
diff --git a/docker/meta/telegraf.yml b/docker/meta/telegraf.yml
index da1aa67..698d4f1 100644
--- a/docker/meta/telegraf.yml
+++ b/docker/meta/telegraf.yml
@@ -1,5 +1,9 @@
 agent:
   input:
+    procstat:
+      process:
+        dockerd:
+          exe: dockerd
     docker:
       endpoint: unix:///var/run/docker.sock
       timeout: 5