Update git submodules

Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "xci: bifrost: Use 'sudo' to install dependencies for bifrost jobs"
  - xci: bifrost: Use 'sudo' to install dependencies for bifrost jobs

    When bifrost jobs are being executed, the virtual environment hasn't
    been prepared yet because that's something that bifrost does later on.
    As such, we need to use sudo to install the required dependencies to
    avoid the following issue:

    Exception:
    Traceback (most recent call last):
      File "/usr/lib/python2.7/site-packages/pip/basecommand.py", line 215, in main
        status = self.run(options, args)
      File "/usr/lib/python2.7/site-packages/pip/commands/install.py", line 342, in run
        prefix=options.prefix_path,
      File "/usr/lib/python2.7/site-packages/pip/req/req_set.py", line 784, in install
        **kwargs
      File "/usr/lib/python2.7/site-packages/pip/req/req_install.py", line 851, in install
        self.move_wheel_files(self.source_dir, root=root, prefix=prefix)
      File "/usr/lib/python2.7/site-packages/pip/req/req_install.py", line 1064, in move_wheel_files
        isolated=self.isolated,
      File "/usr/lib/python2.7/site-packages/pip/wheel.py", line 345, in move_wheel_files
        clobber(source, lib_dir, True)
      File "/usr/lib/python2.7/site-packages/pip/wheel.py", line 316, in clobber
        ensure_dir(destdir)
      File "/usr/lib/python2.7/site-packages/pip/utils/__init__.py", line 83, in ensure_dir
        os.makedirs(path)
      File "/usr/lib64/python2.7/os.py", line 157, in makedirs
        mkdir(name, mode)
    OSError: [Errno 13] Permission denied: '/usr/lib/python2.7/site-packages/pbr'

    Change-Id: I081884ec18d27af19a053bf5b734f6f3846c60f1
    Signed-off-by: Markos Chandras <mchandras@suse.de>