Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge changes from topics 'YARDSTICK-875', 'YARDSTICK-874'
    
    * changes:
      Check if multiverse repository is available in Ubuntu
      Specify supported architectures for Ubuntu backports repository
    
  - Check if multiverse repository is available in Ubuntu
    
    In Ubuntu, multiverse repository is needed to install the image
    dependencies [1]. If this repository is not enabled, it should be
    added as part of the role "add_custom_repos".
    
    [1] https://github.com/opnfv/yardstick/tree/master/ansible/roles/install_image_dependencies
    
    JIRA: YARDSTICK-875
    
    Change-Id: Ie37ebf87bf245185447f2b675568af9bd38219c0
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>
    
  - Specify supported architectures for Ubuntu backports repository
    
    Currently Trusty (Ubuntu 14.04 LTS) and Xenial (Ubuntu 16.04 LTS) doesn't
    have support for arch=ARM64 in backports repository:
    - http://archive.ubuntu.com/ubuntu/dists/xenial-backports/
    - http://archive.ubuntu.com/ubuntu/dists/trusty-backports/
    
    During the Yardstick image building process, the repository is added to the
    APT repository list. In order to avoid errors during the repository retrival,
    the available architectures must be specified [1].
    
    [1]https://github.com/opnfv/yardstick/blob/stable/euphrates/ansible/roles/add_custom_repos/templates/sources.list.j2#L4
    
    JIRA: YARDSTICK-874
    
    Change-Id: I7774189fbdd7d74ff5df29526ba0da2693b3b53a
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>
    

1 files changed, 0 insertions, 0 deletions

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
-Subproject d93f0b4e79bcf822dfb264a82e879f45038628d
+Subproject edb1b87fae318501b853ef02a7aa7dffddfe1e4