pacemaker-remote resources need to be network space aware

[Liam Young]

When a pacemaker remote resource is added to cluster the address for communication with that node is specified. At the moment it just uses the hostname which may not resolve to the correct network space. To correct this:

1) interface-pacemaker-remote needs to be updated to allow the remote unit to specify an ip address for cluster traffic
2) pacemaker-remote charm needs to be updated to set that address with the correct address for the network space being used for the interface
3) hacluster needs updating to consume the new ip address info when creating the resource for the remote node

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/652042

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/652042
Committed: https://git.openstack.org/cgit/openstack/charm-hacluster/commit/?id=27699267edfbf2ce9e5246d6ec89435ab3c4cacb
Submitter: Zuul
Branch: master

commit 27699267edfbf2ce9e5246d6ec89435ab3c4cacb
Author: Liam Young <email address hidden>
Date: Fri Apr 12 11:14:36 2019 +0000

    Use IP supplied via relation for pacmaker remotes

    When setting up resources for pacemaker remote nodes use the IP
    address supplied by the remote node for communication. This
    ensures that communication happens over the desired network
    space.

    Depends-On: I5aa6993ec702f97403d1a659e09a3fb2f5af4202
    Change-Id: I9bb20b5f0b0d780fbf4cc0ac0e5f86fe277c4715
    Closes-Bug: #1824514