change native_charm_centos default touch folder

Signed-off-by: endika <endika.aldecoa@ehu.eus>

charm-packages/native_charm_centos_vnf/native_charm_centos_vnfd.yaml

@@ -23,7 +23,7 @@ vnfd:
             execution-environment-ref: simple-ee
             parameter:
             - data-type: STRING
-              default-value: /home/ubuntu/touched
+              default-value: /home/centos/touched
               name: filename
           id: mgmtVM
           execution-environment-list:
@@ -37,7 +37,7 @@ vnfd:
             parameter:
             - data-type: STRING
               name: filename
-              value: /home/ubuntu/first-touch
+              value: /home/centos/first-touch
             seq: 1
   ext-cpd:
   - id: vnf-mgmt-ext