Increase default ulimit values for Neutron agents containers

For containers where Neutron DHCP, L3 and OVS agents are running
there is limit for number of opened files set.
This limit was configured by default to 1024 which looks that is
quite low and can cause problems even with relatively small number
of networks or routers handled by agent.

This patch increase default ulimit values for those containers to be
16x higher than it was before. Such value should allow to handle much
more routers or networks and shouldn't be too high for any system.

Conflicts:
    deployment/neutron/neutron-ovs-agent-container-puppet.yaml

Change-Id: Ibc8fa0c1ccd4f60ec7c876623a7262003197f67d
Closes-bug: #1824020
(cherry picked from commit 5d3fe630db)

docker/services/neutron-dhcp.yaml

@@ -11,7 +11,7 @@ parameters:
     description: The container image to use for the neutron config_volume
     type: string
   DockerNeutronDHCPAgentUlimit:
-    default: ['nofile=1024']
+    default: ['nofile=16384']
     description: ulimit for Neutron DHCP Agent Container
     type: comma_delimited_list
   NeutronEnableDnsmasqDockerWrapper:

docker/services/neutron-l3.yaml

@@ -11,7 +11,7 @@ parameters:
     description: The container image to use for the neutron config_volume
     type: string
   DockerNeutronL3AgentUlimit:
-    default: ['nofile=1024']
+    default: ['nofile=16384']
     description: ulimit for Neutron L3 Agent Container
     type: comma_delimited_list
   NeutronEnableKeepalivedWrapper:

docker/services/neutron-ovs-agent.yaml

@@ -11,7 +11,7 @@ parameters:
     description: The container image to use for the neutron config_volume
     type: string
   DockerOpenvswitchUlimit:
-    default: ['nofile=1024']
+    default: ['nofile=16384']
     description: ulimit for Openvswitch Container
     type: comma_delimited_list
   ServiceData: