Do not ignore_errors for fallback keyserver
Do not ignore_errors for fallback keyserver

The initial keyserver usage should ignore errors so that
the fallback keyserver can be used. However the second
task should not ignore errors as there is no third
keyserver - if the first has failed, and the fallback has
failed, then the task should fail and the installation
should stop.

Change-Id: I60fdbbde70f9bb14cfdf57e4c357f1cd0fc24f55

os-cloud/openstack-ansible-galera_server,openstack/openstack-ansible-galera_server,os-cloud/openstack-ansible-galera_server,openstack/openstack-ansible-galera_server