Systemd units, limits, and bin path fixes

* Add restart for weave service unit
* Reuse docker_bin_dir everythere
* Limit systemd managed docker containers by CPU/RAM. Do not configure native
  systemd limits due to the lack of consensus in the kernel community
  requires out-of-tree kernel patches.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

roles/network_plugin/calico/templates/calico-node.service.j2

@@ -5,8 +5,8 @@ Requires=docker.service
 
 [Service]
 EnvironmentFile=/etc/calico/calico.env
-ExecStartPre=-/usr/bin/docker rm -f calico-node
-ExecStart=/usr/bin/docker run --net=host --privileged \
+ExecStartPre=-{{ docker_bin_dir }}/docker rm -f calico-node
+ExecStart={{ docker_bin_dir }}/docker run --net=host --privileged \
  --name=calico-node \
  -e HOSTNAME=${CALICO_HOSTNAME} \
  -e IP=${CALICO_IP} \
@@ -24,12 +24,13 @@ ExecStart=/usr/bin/docker run --net=host --privileged \
  -v /lib/modules:/lib/modules \
  -v /var/run/calico:/var/run/calico \
  -v {{ calico_cert_dir }}:{{ calico_cert_dir }}:ro \
+ --memory={{ calico_node_memory_limit|regex_replace('Mi', 'M') }} --cpu-shares={{ calico_node_cpu_limit|regex_replace('m', '') }} \
  {{ calico_node_image_repo }}:{{ calico_node_image_tag }}
 
 Restart=always
 RestartSec=10s
 
-ExecStop=-/usr/bin/docker stop calico-node
+ExecStop=-{{ docker_bin_dir }}/docker stop calico-node
 
 [Install]
 WantedBy=multi-user.target