This commit removes the remainder of openshift_node_facts
role.

This commit removes some items from openshift_facts
for the openshit_node role.

This commit removes schedulable from openshift_facts in
favor of detecting whether or not a host is a master
via inventory.

Currently, debug_level is documented as a way to change
the debug output level for both masters and nodes.

debug_level does not currently have any effect.

This commit removes debug_level from openshift_facts
and properly sets openshift_master_debug_level and
openshift_node_debug_level to the value of debug_level
specified in the inventory.

This commit also reorganizes some set_fact tasks
needed during master upgrades to put all work-around
set-facts for undefined variables in one place, allowing
for easier cleanup in the future.  This includes an
entry for openshift_master_debug_level.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1500164

Filter plugin modules should have unique names to not conflict with core
Ansible modules.  (Ansible 2.4)

Due to a combination of unexpected behavior when resolving filter plugins in Ansible and recent changes to filter_plugins/openshift_node.py, when trying to run a current version of the openshift_node_facts role on a system with an older version of the openshift-ansible-filter-plugins RPM, the role will fail.

  File "/usr/share/ansible_plugins/filter_plugins/openshift_node.py", line 30, in get_dns_ip
    if bool(hostvars['openshift']['common']['use_dnsmasq']):
KeyError: 'use_dnsmasq'

It's not possible for us to have our current RPM version (presently openshift-ansible-filter-plugins-3.5.120-1.git.0.c60f69a.el7.noarch) and a newer RPM installed and run both current openshift-ansible code and older checked-out/vendored releases (for older clusters/releases).

Since only the openshift_node_facts role uses the get_dns_ip filter, move the functionality into a role-specific filter plugin.

In addition, rename the filter plugin to 'node_get_dns_ip' because Ansible is prefering the get_dns_ip from the RPM (ie /usr/share/ansible_plugins/filter_plugins/openshift_node.py) over the role-specific filter plugin of the same name. Ansile prefers the filter plugins in /usr/share/ansible_plugins/filter_plugins/* even when /etc/ansible/ansible.cfg is set to something like:

filter_plugins     = filter_plugins:/usr/share/ansible_plugins/filter_plugins:filter_plugins   <--- yes, 'filter_plugins' before and after /usr/share/ansible_plugins/filter_plugins (ansible 2.3.1.0)

Renaming the filter plugin function ensures that roles that depend on the old implementation can continue to use it through what the older RPM provides, and the new role can use it's role-specific filter plugin without any variable namespace colisions.

Lastly, remove filter_plugins/openshift_node.py since it is now self-contained in roles/openshift_node_facts.