Mount /dev/inside rdma shared device plugin (#32)

Currently rdma resources "/dev/infiniband" are made visible to device
plugin by using hostNetwork.
However, rdma resources updates are not visible to the device plugin container
when kernel modules/drivers are unloaded/loaded if rdma shared device
plugin is already running.

This patch mounts "/dev/" inside the container with which keeps 
tracking rdma device changes.

mounting "/dev/" is required instead of "/dev/infiniband" because
driver may load after device plugin has started, in this case, "/dev/infiniband", does not exist
to begin with.

Signed-off-by: Mamduh Alassi <mamduhala@mellanox.com>

images/k8s-rdma-shared-dev-plugin-ds.yaml

@@ -34,6 +34,8 @@ spec:
             mountPath: /var/lib/kubelet/
           - name: config
             mountPath: /k8s-rdma-shared-dev-plugin
+          - name: devs
+            mountPath: /dev/
       volumes:
         - name: device-plugin
           hostPath:
@@ -44,3 +46,6 @@ spec:
             items:
             - key: config.json
               path: config.json
+        - name: devs
+          hostPath:
+            path: /dev/