Fix: openstack-info: Ensure no newlines in openstack_ports

This makes the openstack_ports variable match the format specified in
the openstack-info metadata (see longdesc). It should be a
comma-separated list of "SUBNET_ID:PORT_ID". It should not be

SUBNET_A
SUBNET_B:PORT_1,SUBNET_C
SUBNET_D:PORT_2,

But rather

SUBNET_A:PORT1,SUBNET_B:PORT1,SUBNET_C:PORT2,SUBNET_D:PORT2

The newlines caused parsing issues in an experimental version of
Pacemaker. Pacemaker is being fixed
(https://github.com/ClusterLabs/pacemaker/pull/3395), but this
illustrated an issue in openstack-info that makes parsing rather
precarious.

openstack-virtual-ip is capable of parsing either format without changes
on a stable release of Pacemaker.

However, looking ahead, it should be updated to use
"attrd_updater --output-as=xml" to query the attribute, as the XML
output is much easier and more reliable to parse. (It should check the
Pacemaker feature set to determine whether XML output is available for
attrd_updater.)

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>