client: ctdb_fetch_lock should check for readonly delegations

client: ctdb_fetch_lock should check for readonly delegations

When readonly delegations were added, ctdb_fetch_lock code should have
been modified to include the check for readonly flags.

Signed-off-by: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Martin Schwenke <martin@meltin.net>
(Imported from commit 78015320b60b0fd0d8c3dc65fbbe3e38e4a02993)