Update git submodules

Update git submodules

* Update docs/submodules/clover from branch 'master'
  - Merge "Implement initial cloverctl CLI tool"
  - Implement initial cloverctl CLI tool

    - Uses client-go package to interface to k8s API and implement
    functions as cloverkube package.
    - Identifies GKE LB IP for clover-controller for user
    - Identifies NodePort port number for clover-controller for user
    if environment is local k8s (assumes flannel CNI currently)
    - Deploys and deletes clover-collector and clover-controller with
    native client-go constructs (currently images are defined with
    local registry). Future work will implement other clover services
    and Istio components. Uses the clover-system namespace.
    - Uses Cobra go package to implement CLI (used in kubectl and
    istioctl) using cloverctl <verb> <noun> convention.
    - Interfaces to clover-controller to configure clover services
    (visibility, IDS ...) within the cluster via REST messaging
    - Start visibility (collector) engine using input yaml file or
    defaults
    - Init, stop and clear (truncate Cassandra tables) visibility
    engine or get basic stats.
    - Add custom rules to IDS from input yaml file and start/stop
    IDS
    - Generate jmeter testplan on jmeter-master using input yaml
    file. Start tests and output log/results from CLI.
    - Specify number of jmeter slaves to initiate tests on from
    CLI. Automatically find IP addresses of jmeter slaves within
    the k8s cluster.
    - Sample yaml files for adding IDS rules, starting visibility
    engine and generating jmeter test plans.
    - Build script to install go and get dependent packages.
    - Implement a custom Istio inject package for manual sidecar
    injection (cloverinject). Currently, unused as it is built from
    Istio 0.8.0/1.0.0 code base.

    Change-Id: Ibb8d08cb98267bdffb8905c221473f177d51bbb3
    Signed-off-by: Eddie Arrage <eddie.arrage@huawei.com>