Update git submodules

Update git submodules

* Update docs/submodules/releng/builder from branch 'master'
  to 6292a126503af27728e3ef73183c36f9fd3d4be9
  - Fix for Pike Jobs Failure

    Problems:
    a. qemu-img not installed in Control Node
    b. Images forcefully converted as raw in compute node
    Fixes
    a. Installed qemu-img in the nodes, before stacking
    b. set force_raw_images as False in nova.conf, this
    will ensurethe images arenot forcefully converted.

    Change-Id: I0305447504c676997fadd867954e43bd35f8c0ad
    Signed-off-by: gvrangan <venkatrangang@hcl.com>