Update git submodules

Update git submodules

* Update docs/submodules/snaps from branch 'master'
  - Adds Stack Update

    Adds function to allow stack update to
    occur.

    Includes higher level object calls for stack
    update.

    Added blocking parameter to create() and update()
    Rebase screwed up some changes.
    Added new test to test_suite_builder.py and updated
    IntegrationTests.rst accordingly

    Change-Id: I4558befb3ea8ea7982faff79d1ebb54fbb3d44a7
    Signed-off-by: mbeierl <mark.beierl@dell.com>