[OVN] Check if exists trunk ports before cleanup

While migrating from OVS to OVN one of the steps of the migration
is clean all the OVS trunk ports, this will fail if the environment
does not have any trunk ports configured.

This will do a comprovation in order to know if it's necessary
to clean them or not.

Also, since this playbook it will only clean the ovn interfaces
it is not necessary to stop the whole migration. If any error
occured while deleting any ovs interface a message will be
printed so the user can take action if necessary.

Change-Id: I6ec0b392b13daa9f64e051fb12b4b97a6c0a1730

tools/ovn_migration/tripleo_environment/playbooks/roles/migration/tasks/cleanup-dataplane.yml

@@ -10,10 +10,35 @@
         ovs-vsctl del-port $dhcp_port
       done
     done
+  register: router_dhcp_error
+  ignore_errors: True
+
+- name: Cleanup neutron router and dhcp interfaces finished
+  debug:
+    msg: WARNING error while cleaning ovs interface with msg {{ router_dhcp_error.msg }}
+  when:
+    - router_dhcp_error.changed
+    - router_dhcp_error.rc != 0
+
+- name: Check if neutron trunk subports need cleanup
+  shell: |
+    ovs-vsctl list interface | awk '/name[ ]*: sp[it]-/ { print $3 }' | grep 'spi-\|spt-'
+  register: do_cleanup
+  ignore_errors: True
 
 - name: Cleanup neutron trunk subports
+  when: do_cleanup.rc == 0
   shell: |
     ovs-vsctl list interface | awk '/name[ ]*: sp[it]-/ { print $3 }' | xargs -n1 ovs-vsctl del-port
+  register: trunk_error
+  ignore_errors: True
+
+- name: Cleanup trunk ports finished
+  debug:
+    msg: WARNING error while cleaning ovs interface with msg {{ trunk_error.msg }}
+  when:
+    - trunk_error.changed
+    - trunk_error.rc != 0
 
 - name: Clean neutron datapath security groups from iptables
   shell: |