Update git submodules

Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "Switch to Gerrit for scenario source urls"
  - Switch to Gerrit for scenario source urls

    In the past, there were cases where the Git mirrors were
    out of sync with Gerrit which caused the use of outdated
    repos. This change switches all scenarios to Gerrit.

    Apart from that, it also aligns the urls across all scenarios.

    Change-Id: I5301630a71446df8668f16c81bf26d81bcea8031
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>