Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Add functest healthcheck test suite

    - Add Functest healthcheck tier to Dovetail as new test suite
    - Intention is that these test cases are not part of mandatory
    test cases in compliance program
    - Use for debug and SUT pre-flight check
    - May consider running tc001 (connection_check) at other
    test execution stages to determine if SUT is still functioning, as
    this test takes < 10 sec (more important as test complexity increases
    such as in vnf test tier)
    - Replacement for patch:

    https://gerrit.opnfv.org/gerrit/#/c/52461/

    - Removed CI filters, as suggested

    Change-Id: I2e72931b27e43359d6250f6959a17af8526c5094
    Signed-off-by: Eddie Arrage <eddie.arrage@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index d596c99..71ba21f 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit d596c9988d82cb6876b0acd12e79a89319bdbd0b
+Subproject commit 71ba21ff906d4104a81442d4712aac13cf4906d4