When a single vnfd is deleted, the following success message is delivered.
$> tacker vnfd-delete cirros-vnfd-multi-vdu
All vnfd(s) deleted successfully
The above success message has to modified to
" All specified %(resource)s(s) %(msg)s successfully? "
Change-Id: I48443622b718a1d6a1476f53c6378b67ce0d82e4
Closes-Bug: #1672302