Add gather_facts to ovs roles

Add gather_facts: false to ovs roles to avoid
Ansible gathering facts twice.

Change-Id: I3a26ac40cd6e4a9c0e16b668bae577a795a1e100
Closes-Bug: #1746396

ansible/site.yml

@@ -330,6 +330,7 @@
         when: enable_opendaylight | bool }
 
 - name: Apply role openvswitch
+  gather_facts: false
   hosts:
     - openvswitch
   roles:
@@ -338,6 +339,7 @@
         when: "(enable_openvswitch | bool) and not (enable_ovs_dpdk | bool)"}
 
 - name: Apply role ovs-dpdk
+  gather_facts: false
   hosts:
     - openvswitch
   roles: