Run gearman server for devstack plugin

We need to run a gearman server and specify it in our config if we want
to support features which require it.

Change-Id: Ibb4d59aca2301438a30d2409e38c01b1c9a3564a

devstack/plugin.sh

@@ -75,7 +75,9 @@ elements-dir: $(dirname $NODEPOOL_CONFIG)/elements
 # the value).
 dburi: '$dburi'
 
-gearman-servers: []
+gearman-servers:
+  - host: localhost
+    port: 8991
 zmq-publishers: []
 # Need to have at least one target for node allocations, but
 # this does not need to be a jenkins target.
@@ -162,6 +164,9 @@ function start_nodepool {
              secgroup-add-rule default udp 1 65535 0.0.0.0/0
     fi
 
+    # start gearman server
+    run_process geard "geard -p 8991 -d"
+
     run_process nodepool "nodepoold -c /etc/nodepool/nodepool.yaml -d"
     :
 }

devstack/settings

@@ -4,4 +4,5 @@ NODEPOOL_IMAGE=$(basename "$NODEPOOL_IMAGE_URL" ".img")
 
 IMAGE_URLS+=",$NODEPOOL_IMAGE_URL"
 
+enable_service geard
 enable_service nodepool