vhost: log socket path on adding connection

vhost: log socket path on adding connection

Add log print of socket path in vhost_user_add_connection.
It's useful when adding a mass of socket connections,
because the information of every connection is clearer.

Fixes: 8f972312b8f4 ("vhost: support vhost-user")
Cc: stable@dpdk.org
Signed-off-by: Gaoxiang Liu <liugaoxiang@huawei.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>