Pin Tempest to 29.0.0 tag for stable/wallaby testing

Stable/wallaby is in Extended maintenance state[1] and
Tempest master stopped supporting the stable/wallaby[2] so
we need to pin tempest in stable/wallaby testing.

We use Tempest 29.0.0 compatible tag for wallaby testing.
Due to constraints of teststool 2.4.0 in stable/wallaby[3],
Tempest>=30.0.0 (which removed the workaround of testtool
issue[4]) fail on stable/wallaby with SkipTest are treated
with error[5]. That is why we need to use Temepst 29.0.0
which is compatible with testtool 2.4.0.

Making openstacksdk-functional-devstack job non voting as this is
failing 100% on <=stable/xena
- https://zuul.openstack.org/builds?job_name=openstacksdk-functional-devstack&branch=stable%2Fxena&branch=stable%2Fwallaby&skip=0

Depends-On: https://review.opendev.org/c/openstack/tempest/+/871781
Depends-On: https://review.opendev.org/c/openstack/devstack/+/871945

[1] https://releases.openstack.org/
[2] https://review.opendev.org/c/openstack/tempest/+/864371
[3] 35c167b04c/upper-const>
[4] https://github.com/testing-cabal/testtools/issues/272
[5] https://zuul.opendev.org/t/openstack/build/0a42465205484a72adaab7d8a116d823/log/job-output.txt#2>

Change-Id: I9a8fad5c1f13107dcd6c23c281bae6a42a10294f

.zuul.yaml

@@ -691,7 +691,10 @@
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
+        # TODO(gmann): make it voting once it is fixed, currently it is failing
+        # for <=stable/xena https://zuul.openstack.org/builds?job_name=openstacksdk-functional-devstack&branch=stable%2Fxena&branch=stable%2Fwallaby&skip=0
         - openstacksdk-functional-devstack:
+            voting: false
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
@@ -722,10 +725,11 @@
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
-        - openstacksdk-functional-devstack:
-            irrelevant-files:
-              - ^.*\.rst$
-              - ^doc/.*$
+        # - openstacksdk-functional-devstack:
+        #    voting: false
+        #    irrelevant-files:
+        #      - ^.*\.rst$
+        #      - ^doc/.*$
         - tempest-ipv6-only:
             irrelevant-files:
               - ^.*\.rst$

stackrc

@@ -297,8 +297,8 @@ REQUIREMENTS_BRANCH=${REQUIREMENTS_BRANCH:-$TARGET_BRANCH}
 
 # Tempest test suite
 TEMPEST_REPO=${TEMPEST_REPO:-${GIT_BASE}/openstack/tempest.git}
-TEMPEST_BRANCH=${TEMPEST_BRANCH:-$BRANCHLESS_TARGET_BRANCH}
-TEMPEST_VENV_UPPER_CONSTRAINTS=${TEMPEST_VENV_UPPER_CONSTRAINTS:-master}
+TEMPEST_BRANCH=${TEMPEST_BRANCH:-29.0.0}
+TEMPEST_VENV_UPPER_CONSTRAINTS=${TEMPEST_VENV_UPPER_CONSTRAINTS:-$REQUIREMENTS_DIR/upper-constraints.txt}
 
 
 ##############

tests/test_refs.sh

@@ -15,7 +15,7 @@
 
 echo "Ensuring we don't have crazy refs"
 
-REFS=`grep BRANCH stackrc | grep -v 'TARGET_BRANCH' | grep -v 'NOVNC_BRANCH'`
+REFS=`grep BRANCH stackrc | grep -v 'TARGET_BRANCH' | grep -v 'NOVNC_BRANCH' | grep -v 'TEMPEST_BRANCH'`
 rc=$?
 if [[ $rc -eq 0 ]]; then
     echo "Branch defaults must be one of the *TARGET_BRANCH values. Found:"