Do not use single item lists for nodes
JJB sometimes gets confused with single item lists for nodes, so change
the few occurences we have to  not use a list.
- pypi-jobs
- openstack-releasenotes-jobs
- gate-{name}-pylint-{node}:
- node:
- - ubuntu-xenial
+ node: ubuntu-xenial
- gate-osbackup-{name}-dsvm-{node}{suffix}:
node: ubuntu-xenial
suffix: ''
- pypi-jobs
- openstack-releasenotes-jobs
- gate-{name}-pylint-{node}:
- node:
- - ubuntu-xenial
+ node: ubuntu-xenial
- gate-osbackup-{name}-dsvm-{node}{suffix}:
node: ubuntu-xenial
suffix: ''
