Update git submodules

Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge changes I15f5d41f,I7c7125ac

    * changes:
      Export CI_LOOP as expected by Functest
      Export an new var related to Energy

  - Export CI_LOOP as expected by Functest

    CI_LOOP is hardcoded to daily (the common default value) [1].

    [1] https://gerrit.opnfv.org/gerrit/#/c/51981/

    Change-Id: I15f5d41f7f10a5c8fddcc4a4d303552ef45c5fb2
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
  - Export an new var related to Energy

    It conforms with "Unlink Energy from functest utils and constants":
    https://gerrit.opnfv.org/gerrit/#/c/51943/

    Depends-On: Iecd5d49b4d4c961c9dc51e43e54df1fcd4027266
    Change-Id: I7c7125ac2fee9a2e8f24dcf060bdaab1b39ae552
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>