Update git submodules

Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Merge "Bugfix: the config files in useeconfig will cover user's config"
  - Bugfix: the config files in useeconfig will cover user's config

    1. Now there are 2 sample files tempest_conf.yaml and hosts.yaml in userconfig,
       and thet will cover user's tempest_conf.yaml and hosts.yaml
       in $DOVETAIL_HOME/pre_config.
    2. Rename the files in userconfig to be tempest_conf.yaml.sample
       and hosts.yaml.sample.
    3. Add the hosts info in file /etc/hosts in Dovetail Container.

    JIRA: DOVETAIL-492

    Change-Id: I2b5694a8058b864b510925eec595d6f2bd1062ff
    Signed-off-by: xudan <xudan16@huawei.com>