Use template for lower-constraints

Small cleanups:

* Use openstack-lower-constraints-jobs template, remove individual
  jobs.
* Sort list of templates

Change-Id: I08349e13587b16f91f0433c6f559bd7089517784
Needed-By: https://review.openstack.org/623229

.zuul.yaml

@@ -1,10 +1,11 @@
 - project:
     templates:
+      - check-requirements
       - openstack-cover-jobs
+      - openstack-lower-constraints-jobs
       - openstack-python-jobs
       - openstack-python35-jobs
       - openstack-python36-jobs
-      - check-requirements
     check:
       jobs:
         - monasca-tempest-python-influxdb
@@ -13,7 +14,6 @@
         - monasca-tempest-python-cassandra
         - monasca-tempest-java-cassandra
         - monascalog-tempest
-        - openstack-tox-lower-constraints
         - docker-build-monasca-base
         - legacy-monasca-common-maven-build
     gate:
@@ -23,7 +23,6 @@
         - monasca-tempest-python-cassandra
         - monasca-tempest-java-cassandra
         - monascalog-tempest
-        - openstack-tox-lower-constraints
         - legacy-monasca-common-maven-build
     post:
       jobs: