Update git submodules

Update git submodules

* Update docs/submodules/releng/builder from branch 'master'
  to 1e61f2d92db60a5e5dff3cd42417542bb7f7a9fe
  - Merge "Install mvn via lf-maven-install macro"
  - Install mvn via lf-maven-install macro

    The macro is currently our standard way to get Maven onto a system.
    Also add mvn-version variable to allow the template to be overrided
    with a different version by the projects.

    Change-Id: Icc0e945f344ddaddb9b2b865c7ed165fda6fe46d
    Signed-off-by: Thanh Ha <thanh.ha@linuxfoundation.org>