Correct config help message related options

The options list in 'Related Options:' section doesn't rendered
as bulleted list for some params because of missing blank line.

This changes adds missing blank line wherever needed in [1].
[1] https://docs.openstack.org/nova/latest/configuration/config.html

Change-Id: I7077aea2abcf3cab67592879ebd1fde066bfcac5
(cherry picked from commit ac42c43)

Author: ratailor

nova/conf/ironic.py

@@ -27,6 +27,7 @@
     help="""
 Configuration options for Ironic driver (Bare Metal).
 If using the Ironic driver following options must be set:
+
 * auth_type
 * auth_url
 * project_name

nova/conf/libvirt.py

@@ -987,6 +987,7 @@
 according to the poll interval.
 
 Related options:
+
 * images_type - must be set to ``rbd``
 * images_rbd_glance_store_name - must be set to a store name
 * images_rbd_glance_copy_poll_interval - controls the failure time-to-notice

nova/conf/mks.py

@@ -23,7 +23,9 @@
 instance console access to VM's created by VMware hypervisors.
 
 Related options:
+
 Following options must be set to provide console access.
+
 * mksproxy_base_url
 * enabled
 """)

nova/conf/vmware.py

@@ -76,7 +76,9 @@
 * Any valid URI (The scheme is 'telnet' or 'telnets'.)
 
 Related options:
+
 This option is ignored if serial_port_service_uri is not specified.
+
 * serial_port_service_uri
 """),
     cfg.StrOpt('serial_log_dir',
@@ -112,6 +114,7 @@
 then the default CA truststore is used for verification.
 
 Related options:
+
 * ca_file: This option is ignored if "ca_file" is set.
 """),
     cfg.StrOpt('cluster_name',
@@ -158,7 +161,9 @@
 * Any valid port number within 5900 -(5900 + vnc_port_total)
 
 Related options:
+
 Below options should be set to enable VNC client.
+
 * vnc.enabled = True
 * vnc_port_total
 """),