Update git submodules

Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Merge "ci/deploy.sh, lib.sh: Align SSH_KEY with Jenkins"
  - ci/deploy.sh, lib.sh: Align SSH_KEY with Jenkins

    Jenkins defines a build param also called SSH_KEY, which holds
    the full path to our MCP private RSA key, as opposed to Fuel@OPNFV,
    which uses the file basename as SSH_KEY.
    Switch to using full path in SSH_KEY, while also moving the key
    outside /tmp.

    NOTE: When running `ci/deploy.sh` with sudo, key will land in
    /root/opnfv/mcp.rsa unless SSH_KEY is set via env var.

    While at it, bring back VM image storage dir param, allowing us
    to drop one more reference to /tmp.

    JIRA: FUEL-280

    Change-Id: Id1cfa6dbe7b2e6f3915b22281da5957333718401
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>