neutron-ha-tool: fix monitor return code
When neutron routers need migration, make neutron-ha-tool's monitor
action return OCF_ERR_GENERIC not OCF_NOT_RUNNING. This is based on the
OCF Resource Agent Developer’s Guide, which says in the section for
The action returned a generic error. A resource agent should use
this exit code only when none of the more specific error codes,
defined below, accurately describes the problem.
The cluster resource manager interprets this exit code as a soft
error. This means that unless specifically configured otherwise, the
resource manager will attempt to recover a resource which failed
with OCF_ERR_GENERIC in-place — usually by restarting the resource
on the same node.
and also in the section for OCF_NOT_RUNNING:
If the resource is not running due to an error condition, the
monitor action should instead return one of the OCF_ERR_ exit codes