Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Update global-jjb to v0.17.0

    Since the commit submodule commit can't be set to an explicit tag,
    please see this link[1] for verification that
    90e4e825b3d0ac5959122c50e457419ad0cfe137 is v0.17.0.

    [1] https://gerrit.linuxfoundation.org/infra/#/c/9386/

    JIRA: RELENG-398
    Change-Id: I9d4e90cc073c8b9cb741735a2ba582a2c7882087
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index bffc847..7d99dc0 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit bffc84719fb9846add3794e33f3e375b0f3c664b
+Subproject commit 7d99dc08b6913d2a0202b092c184c364872b891e