Fix .gitreview and tox to use stable/ocata

NB the ansible-role-requirements are not changed, since we are waiting
on a stable/ocata branch for monasca-api upstream role.

This is being handled in: https://review.openstack.org/#/c/430767/

Fixing gitreview is important for right now though.

Change-Id: I7b2793ef61b6d16b35c07deea36a0f32b286ebff

.gitreview

@@ -2,3 +2,4 @@
 host=review.openstack.org
 port=29418
 project=openstack/openstack-ansible-os_monasca.git
+defaultbranch=stable/ocata

tox.ini

@@ -7,7 +7,7 @@ envlist = docs,linters,functional
 [testenv]
 usedevelop = True
 install_command =
-    pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
+    pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt?h=stable/ocata} {opts} {packages}
 deps =
     -r{toxinidir}/test-requirements.txt
 commands =
@@ -56,7 +56,7 @@ commands =
 [testenv:tests_clone]
 commands =
     bash -c "if [ ! -d "{toxinidir}/tests/common" ]; then \
-               git clone https://git.openstack.org/openstack/openstack-ansible-tests {toxinidir}/tests/common; \
+               git clone -b stable/ocata https://git.openstack.org/openstack/openstack-ansible-tests {toxinidir}/tests/common; \
              fi"
 
 
@@ -83,7 +83,7 @@ commands =
 [testenv:ansible]
 deps =
     {[testenv]deps}
-    -rhttps://git.openstack.org/cgit/openstack/openstack-ansible-tests/plain/test-ansible-deps.txt
+    -rhttps://git.openstack.org/cgit/openstack/openstack-ansible-tests/plain/test-ansible-deps.txt?h=stable/ocata
 
 
 [testenv:ansible-syntax]